Cylinder Misfire code

iv got an 06 liberty as well. . . . i had a problem wit it doing the same thing but it ended up just being a clogged catilatic converter n after the dealer replaced it then its been just fine. . . my jeep had 45000 or so on it when this happened

mine is a 2007 jeep lib. #4 misfire new plugs and coil pack on #4 light came back on after 300 miles if you find anything new please post

My jeep Liberty 2009 does the same the Dashboard showed a code of cylinder 3 missfire , but after 1 hour the light is gone and showed no problems , but the jerking remains , to be accurate it happens like this : - no jeking problems at the start from stop . - when above 30 mph and accelerate , at same time jerking happens and feels like engine is gonna die , and he car vibrates 2 or 3 times .- - during the jerking moment , if i left my foot up the jerking stops . not yet taken to the dealer ,, iv'e read about this problem alot , looks like its common , and most of ppl paid hell alot of greens for nothing and problem was not solved . so ma having second thoughts about leeting those stupid dealers into my pocket to suck it dry !! i think he problem would be the same old " Heat soak @ which was very common in old models 1999-2002 , same symptoms i see . have you solved your problem ? please reply to me if you did , Thanks .

I have the same problem with my 05 Lib and I was told to change the ASD relay (under the hood on the right, in the front), I did this and it stopped acting up for about 100 miles and then it started to misfire again, I pulled over and shut it off and restarted it and it ran fine again, so, my guess is that it has something to do with the ASD relay ($14.69 at Napa)

I had the same issue with my 2009 Jeep Liberty Limited Edition. Check engine light, misfire, etc... Took it to the mechanic and after replacing the spark plugs the trouble disappeared for a couple of months... Now I'm back to square one, however, the misfire is not as rough as before. I only notice the misfire when idling, and that causes the engine light to come on. However, now there is no code after the self check diagnose. Any help/ideas to what to do next? Your help is greatly appreciated.

Most likely a vacuum leak. This happened in my Ford Expedition and it turned out to be a hole in a vacuum line that goes from the back of the throttle body to the valve cover. Heat and vacuum caused the line to degrade and suck in causing a hole in one of the rubber fittings. I found a piece of alluminum tubing and took the ends off of the fitting and put the ends on the tubing with pipe clamps and replaced it. Works great.

Thanks Tfas4U... My mechanic had mentioned that as a possibility, however, I think that if the problem was there and gone with changing of the spark plugs. How come it stopped misfiring for 2-3 months, and now is back? Having said that, I will have the mechanic smoke the lines for a leak... Also, important to mention that this seems to be a common issue with these cars and so far I haven't found a straight up answer to the problem. And I've searched in plenty of forums sites.

I actually found the problem. In both the 4 cylinder and 6 cylinder Jeeps, the valve cover gaskets have a short life and as they encircle the spark plugs, oils leaks down on them and shorts them out. Gasket changed, problem solved. Thanks for all the rest of the advice and your answers though!

Thanks Teratura, you sound very convinced that the Valve cover gasket is the solution to this problem. I really hope so. Do you know how much this job would cost? I know the valve gasket is about $40 here in Canada. The question is how much should I expect to pay to the mechanic to replace it.

Here in Maine, my Jeep was still under warranty, I did, however, see the invoice and it was a little over $400. The gasket here in the US was $86, so the Canadian prices may be way different than ours here. Your local mechanic may give you an estimate for it before they do the work. Mine was done August of 2013 and it hasn't skipped since.

The injectors have a tendency to partially clog. Pull injectors, spray tip w/carb. cleaner and blow out with compressed air. this is the best way to clean them. instead of one hole, they have four smaller ones. Don't force anything into holes......Ive tried the Canister/pressurized type, without much luck....

i have a jeep liberty 2006 with the # 5 cylinder misfire. i replaced the sparks plugs, coil pac, pcv valve,air filiter,oil change belt replaced, complete tune up and still the same problem. engine light is on and shakes when it idling. please help.

I have a 2001 Jeep Grand Cherokee the check engine light came on as misfire cylinder 3 I replaced it I also replaced the coil pack and the spark plugs then came on for bank 1 sensor 1 fixed that now the check engine light keeps coming on for all the problems I fixed already I do not know what else to do not sure if I have a leak somewhere but it's thinning my oil out now that my oil pressure dropping anyone ever have this please let me know thanks

The 3.7 and 4. are really bad about dropping a rocker because of the dirty lash adj. If its tapping and hear a knock...that's what it is..easy to do..buy new lash adj and gasket off ebay.. if your throwing a code 9030? and sounds like that that's what it is..

P030? sorry

I have a 2005 Jeep Liberty 6 cylinder, engine light came on scaned the codes it said P2311 and P2314 cylinders 4 and 5 so I put new plugs and coil wires on and P2314 code cylinder 5 went away but P2311 code cylinder 4 is still coming up checked the plug harness that plugs onto coil wire looked ok no corrosion or cracks, so I don't know, the only thing I didn't do was check to see if their is any electric current coming out of the plug that plugs onto the coil wire, any help would be appreciated

Just finished putting in a used engine in my 2002 3.7 liberty. Fired off great and once warmed up started miss firing. Code showed miss fire on #4 and #6 cylinders I did the typical swap coil packs. Pulled the fuel rail and checked all of the fuel injectors. Fixed a minor fuel leak in the rail on the drives side, and changed all o-rings on the injectors. Even swapped the drives and passengers injectors to see if the problem would follow. Checked all connectors for corrosion, no problems there. Fired it up and still miss firing on #4 cylinder only. Finally checked the spark plug gap on that cylinder, it was .020 instead of the factory spec of .040. If a plug is gaped to close it won't spark because there isn't enough space for the spark to be created. Found out #6 was at .035. Regapped all plugs to factory spec. Put it all back together fired it up, check engine light went off, and the engine idles smooth. I don't know if this fix for everyones idle issues,but apparently spark plugs are a touchy issue for these jeeps. I was told only to use the factory spec plugs, and obviously gap them correctly.

did changing your valve gasket actually work

It was weird mine stopped misfiring after I had changed the fuel filter

Well I have a 2011 jeep liberty I had change almost everything from alternator, oxygen sensors to the coil packs. And the problem was the whole time was the spark plugs. Everything that was happen to you' ll car mine was doing the same thing so to all of you'll its the spark plugs.

Replace the ignition coils and spark plugs. If that doesn't work then its the computer wiring. Had it happen twice with two different '02 liberties.

It would seem that this is a very very serious issue with these jeeps, to numerous to count and dangerous to be operating on the roadways. How many have reported this serious huge issue to the National Highway Safety Council as a vehicle complaint so the manufacturer would be forced to recall these vehicles to address and fix this safety issue?

My Jeep Liberty was having misfires I had to take the valve cover off and put the rockers back on they pop off once in awhile

I have a Jeep Liberty 2003 and was having the same issues. Misfire on #6 and check engine light coming on. When you have a misfire it shuts off the injector so fuel doesn't go through. That is what causes the shaking when you go over 10-15mph. Changed spark plugs myself, worked for about 3 weeks. Check engine light came back on. I took it to a mechanic and he couldn't really figure out what was going on, so I took it to a Jeep specialist and he cleaned the injectors. It seem to work for about a month, then it had the code again (misfire #6 and check engine light on). Took it back and asked the specialist what would happen if he move the #6 injector to another spot and see if it misfires there. So he cleared the code and swapped #6 to #4, then drove it around. Sure enough check engine light comes back on and the misfire is now on #4. So I had them replaced all injectors and the problem went away. It has been about a month and half and the jeep still runs good with no problems.

I've got an 02 Liberty Limited edition with a cylinder 5 misfire that causing the check engine light [CEL] to be on. My mechanic knows this Jeep well since he installed 2 re-manufactured engines from a company called Power Train Products. In October of 2015 first engine failed within 20 miles due to coolant getting into the oil, 2nd engine was installed in November and has run well until May when this misfire had begun. Mechanic changed the plug and coil pack, CEL came on again in about 20 miles. He swapped the injector to cylinder 3 and the coil pack to cylinder 4 and CEL comes on still with a mis-fire code on #5. 2 days ago CEL mysteriously goes off and needing a NYS inspection I a put 50miles on it and IMMEDIATELY drove to my mechanic it passed since the miles were enough to have the code wiped from the computer. Pulled out of the shop and CEL lit up again. My mechanic said next thing he'd do is to open up the valve cover and see if anything is obvious. I mean I would not think this is engine related since the re-manufactured engine has less than 15K on it since installing, but then again one of Power trains engines failed right out of the box. I really hope it's something that has been overlooked, i purchased this jeep for a buddy in July of 2015 with ~115K and has been nothing but problems since.

I have 03 liberty kept getting multiple misfire code had dealer tell me it was coil packs about 120 bucks apiece and want to charge 300 bucks in labor , a friend of mine drove it and thought it was fuel injectors I bought all 6 injector s off from rockauto.com I believe it was 100$ for all 6. Changed them and rain premium gas for a month and never had a problem since

My 2003 Jeep Liberty warms up after about 5/ 10 minutes then sputters and stalls. The tachometer jumps up and down. 2000- 300.rpm Does this and sometimes quits. Always restarts. Changed plugs, crank, can sensors. Code comes up speed sensor malfunction??? Please help

@jeepers74. Idle position sensor is my first guess does it keep running with foot on gas?

Im having the same issue with my 02 liberty sport. Yesterday ( 9-23-16 ) she ran fine.. I go to this morning and it's running horrible only will stay running if I keep my foot on gas. And aftet about 1-2 minutes of me trying to keep it running the check engine light will start to flash it's only happened once to me so far as soon as I saw it I shut it off. But it is running extremely horrible and I noticed when I very very first started it this morning and I was trying to keep it running a bunch of white smoke is coming out of my exhaust but after about 30 seconds it completely went away but still was idling really bad. It would not say running if I took my foot off the gas.

I just got an 03 liberty and it us misfiring #4, engine light on, sralls sometimes going diwn the road. I put the reader on it and reset it and it'll run forva day ir two without me keeping foot on gas. They just put new plugs in it when I bought it. Very frustrating.

I just purchased a 2003 Liberty and sometimes when I start it up I get multiple cylinder misfires. I forget which ones but I want to say 1, 3, 4. If I turn the vehicle off and start it up again the misfires go away and drives just fine. I believe the coil packs are OK because of how rare and random this is, so my next guess is what controls the coil packs?

2002 jeep liberty 3.7l has a code for a misfire in slot #1 i changed the ignition coil and spark plug even have 6 extra fuel injectors and I've put two different ones in and it is still coding, and running rough. Now i've just found a leak on the left side coming from the fuel rail. I'm not sure why it's doing this. I've been working on it about 4 days now and can't figure out what the problem is. If any knows of anything let me know. thanks

mine doing it changed the plugs coils injectors and crank sendor still running bad help

04 jeep liberty reservoir is above coil packs. check for leaks, cracks or water drips on coil packs and wiring. Check if there are any areas that appear total clean. This is a sign water is dripping and steaming off. May or may not smell radiator fluid. If code is on cylinder 4 or 6 water gets in the electrical connections and shorts across, causing misfire. p 0304

I have an 04 jeep liberty limited and my check engine light is on stays on what could cause that to happen

Wow, you guys are working this to hard. Pull coil on cylinder.one nut to remove. Ohm out coil. Info is on replacement website at Auto zone. Second if it is 4 or 6 check for leak at reservoir. Make sure their is a rubber boot at bottom of coil, prevents water and moisture build up around coil base.Third option. Very small insulation at connector where coil wires touch, insulation goes bad due to moisture and age. Wrap with electrical tape separate wires; inserting tape between wires. The coil is shorting to ground most likely. Had this problem on my jeep. Coil had internal cracks was shorting to ground thru housing. All due to moisture over time. $24 dollars and some electrical tape. Look hard at coil it will show slight scaring. Wire insulation shows slightly white. Just pull them slightly apart slide a piece of electrical tape between then wrap the back together. Clean the connector. And post the code next time if you can it helps to help you.

Also a possible reason your not shifting correctly is because the computer is not kicking in the Overdrive on the transmission. Because it is sensing an abnormal load condition due to cylinder misfire. Kick off the overdrive on your shifter for just a minute and see if it helps with shifting. I expect it will. It is the small button on the shifter knob. Left side halfway down. Do not leave it off. Just click it off for a moment. By the way the test for the coil is listed under the AC Delco replacement coil. And for diagnosis. We use probable causes. What could cause it. Gas, compression, spark, timing of spark. Then we take the most probable cause. After we determine that we have the basics. That meets the criteria of symptoms. Then we test are assumptions. Then where supposed to determine what caused the problem. To keep it from repeating . I see alot of guessing on this page. With very little testing. If you are paying someone to test your vehicle or testing it yourself. Please follow these steps. And get answers to these steps from the people you pay before they do any major work. Otherwise you are wasting your money and time. While there are other possible causes to this problem. The electrical probability of a shorting coil or wire. Easily tested with a multimeter and visual inspection. Is the highest probability that meets the drivability symptoms.

Girlfriends 04 Jeep Liberty has a multi cyl misfire code and it turned out to be all 4 O2 sensors. Codes are all gone (couple months now) but just yesterday it started doing a misfire like startup. Does anyone know how much back pressure these 3.7L need to run properly? Want to make sure I narrow it down to a prime issue before dumping anymore money into this thing. (Rear dif went out in May, O2 in July)

Guys, O2 sensor so not cause misfires. They simple tell a computer wether your fuel is low or high on oxygen. Misfires. Are caused by timing, shorts, fuel or compression. The one being described. Is most likely a bad coil. Ac delco makes a great set for jeep. 6 for about $99.00 at Autozone. They come with an extra boot. That covers the spark plug to protect it from fluids. The answer to back pressure is between 2-4 pounds in most cases. If your worried about a plug. Disconnect it and look thru it. If you can see thru the honeycomb your fine. If you have been running rich. Disconnect o2 sensors. Cause lean condition while computer is in base mode. 10- 15 min or until it gets hot. Do not melt it. Seriously. This will clean it. But so will chevron techron. Liquid gas tank.work have tested. With a gas analyzer. Works. Do not punch or take it out long-term. No back pressure causes premature wearing of exhaust valves long term.And honestly guys and gals. Most misses are caused by coils or spark. Jeep does have a head problem, if you spike temp. So a good way to test if it is any computer controls. Is just force it in to base mode by disconnecting the O2 sensor. If it still does it. Isolate problem switch coil packs, use flash light check cylinder and spark plug. Look for water, leaks burn marks. Check color of spark plug. Old school but tell you alot. Best of luck.

these are some possible reasons for the misfires

I purchased this book from https://www.rockauto.com/

Guys and gals. Happened to me. Found two things. Problem is fixed has not come back. First most likely coil wire at connection to spark plug. Replace with ac delco coil pack after inspecting present coil wire connector for burns or cracks. Second. The grounds on this vehicle stink. Love my jeep but clean up the ground connections to the body and engine.

Yes Guru2RQN, I just changed the ignition coils and misfire seems to be gone...i guess we'll wait and see. some of the old coils were cracked and in very bad shape.

The guy Guru2RQN , is very smart everyone get it together he knows what's going on .. his explanation on the diagnostic is dead nuts ..

Thank you. One extra for anyone who decides to swap engines. A few years ago. I decided I wanted a brand new crate engine. So I started calling around. Annoyed everyone by price haggling for weeks, not days. Got Bill Smith Jeep dealership out of Idaho to ship a brand new crate 3.7 liter. For only $1200 to my local dealer. Good luck and thank you for the recommendation.

Currently having this problem. Running a p0420 code and changed the O2 sensors. Misfire subsided for about a day. Misfire came back and got a lot worse. Jeep finally through a p0350 cylinder 5 misfire. Changed the coil pack and spark plug and the misfire never went away. Still throwing a p0420 code. Can a clogged cat cause a misfire?

Plugged cat causes a stall and sluggish running then stumble. May sound simple. Are you sure you connected all the sparkplugs and coils back in the proper order. Do not overlook simple things. Also p0350 is a general misfire. Not isolated to cylinder 5. Unless your scanner is reading that directly. Check simple. Disconnect o2. Does it still do it.? If it stalls immediately check for air leak. Or carbon on throttle plate. If it still chugs it in not computer controlled problem. Pull o2 sensor. Eliminates computer and exhaust. What did the sparkplugs look like. Did you gap them or did you just install them. If you installed without measuring the gap yourself. Re gap them this is a very likely fix. Check for water around cylinders. Moist areas. Water sometime leaks down from reservoir and can short cylinders. Most likely though it is something simple you missed. You can also check ECM ground on right side by battery. Very unlikely though. Code changed. New components would not have caused this code change. Directly in most cases. Check sparkplug gap. Text me back with results of examination. Use brite flashlight. Check for exposed wiring to injectors while your there, unlikely but possible.checking injectors is last. How many miles do you have on vehicle?

I check things. I do not like wasting money.

Hi ask that you make a good decarbonization to your combustion chambers and full of admission these engines generate a lot of carbon.

Hi ask that you make a good decarbonization to your combustion chambers and full of admission these engines generate a lot of carbon.

Just use some techron every once in awhile. Then no worries. Have cleaned up many a car this way. The exception to this are old el Camino's and some classics that bake carbon in to solid plugs in their EGR gasket ports. Almost exclusively, they were all running penzoil oil and had large sludge deposits in addition to heavy carbon deposits. Occasionally carbon and sludge build up in happened to Evos and Hondas as well. All the rest of the vehicles I have worked on. Techron was enough to clean them up internally of both sludge and Carbon. This I have tested with both physical inspections and smog machine tests.

Got a 2005 liberty with the 2.4L manual trans. At wide open throttle, it just loses all power and stalls out around 3200 rpm and doesn't move. Doesn't throw a code. The only codes were the gas cap being loose, an o2 sensor that was destroyed and an acorn being stuck in the idle air control valve. Runs solid and shifts fine through town where speed limits are low. But any interstate travel is laughable or dangerous, or if I needed to speed up for any reason I'm a dead duck.

Few possibilities, catalytic converter is getting plugged. Two an intake air leak that's not being measured. ? Does the exhaust get really hot. How was the O2 sensor destroyed. Heat? Or carbon foul. Back pressure from cat could shut you down. Intake air leak after the throttle valve, possible but should throw code. So should plugged cat. But maybe not. ? Did you bypass any components. And have you checked your timing marks. Really need a little more description to help. Anything else is guessing.does cat glow. Hear cracking noises from exhaust. Main question is why did O2 sensor go down. Heat or carbon. Sound like cat, or exhaust backing but no way to know without more information.

So I have a 2003 jeep liberty. Check engine light stays on. P303. I have changing all spark plugs and coils and injector in cylinder 3. Light still on and flashing now saying p300. Help me. Idk what else is wrong. asd relay works because we tested it and switched with blower relay.

Does it feel like it's losing power?

On my 2006 (4cyl) found out the spark plugs go through the intake housing cover. The gallery was bad, it leaked oil down to my spark plugs causing them to foul and indicating a misfire. Change the intake cover gasket and change plugs, it'll be good for another 90 thousand unless you get the premium gasket set. Garage costs about $500 to do it.

Ok thank you. I feels like its gonna cut off. I just changed the plugs twice because i kept misfiring and then the fuel injectors. So It maybe the intake cover gasket and just get new plugs?

How do I know which gasket it is? I was reading somewhere that liberty has a driver and passenger ?

First did you make sure to check the gap on the spark plugs. Second have you taken a flashlight and looked in the gallery to see if their is any water or oil. Third have you looked at the coil packs for scaring, scorch marks or cracks. Is their any moisture on top of the spark plugs. This would cause a short. Look don't guess.

My daughter's 2008 Liberty had error codes for cylinder 2 misfire. Had the coil & plug replaced and runs well. Just noticed that one of the lines to the AC compressor runs immediately over the coils on the passenger side. Water condenses on the AC line and drips directly onto the coils including the new one. I think I found the problem. Bad design to place an AC part that drips condensation directly onto electrical parts.

To anyone having the misfire problem, change your fan clutch. The fan in front connected to the motor. I had the misfire issue with the blinking check engine light issue. I'd changed my 02 sensors, crank and cam, plugs and coil packs, and the relay people kept mentioning. I found a thread about the fan and changed it and changed the plugs again and misfire gone.

I found the solution to all of these issues. Buy the largest sledgehammer you can find and smash everything in sight. Buy a new vehicle..anything but Jeep.

2015 3.7 carbon on valves Try professional cleaner through intake vacume line or replace bad valves. That's the only fix for a cold start miss.

I have a 06 Liberty and mine is beginning to have the misfire issue but it’s ONLY when the vehicle is wet! Is this the case with everyone else? Could just be moisture getting to the wires or nearby ground? When it’s cold, the check engine light goes off and runs fine.

My Answer comes with a story, sorry. My AC compressor locked up and started popping belts on my 3.7L Liberty so I took it in to the shop. Pay the giant bill and go for the first ride but after 20 miles the engine light turns on. Now, the Jeep is not running bad in anyway. Not losing power at certain speeds, not rough idling and not odd sounds or smells so misfire is the the last thing I'm thinking when I read the codes. Sure enough, I'm getting P0300, P0304 and P0306. Codes I didn't have when I brought it in. They would have had to disconnect and pull off many parts on that side to do the AC install and sure it's plasaplbe 4 and 6 coil packs or connectors could have come loose or shorted. Took it back and switched 2 with 4 because that's all I could reach and the engine kept running like nothing happened, cleared codes and drive around the Block and the same came back. I do IT work for the owner on occasion and I'm sure this came into play. They took it in pulled everything off the that side of the engine, replaced the coil packs, the wires, the connectors, spark plugs and anything else that can cause misfires with or without symptoms. Not a darn thing found as a cause. Next day I bring in a PC I fixed for onc mechanic and donuts and coffee for the whole shop. Turns out the owner did a lot of research online and calling around to all his expert mechanic friends and has come up with one conclusion; carbon build up on the valves. One or two cans of seafoam is all I need. OK I'll try it but I sile in socal where neighbors get triggered when they see large plumes of white smoke for ten to 20 min. A buddy and I took it out to a deserted road a few nights later, followed the directions exactly. NO MORE MISFIRE CODES and it's been 2 hundred miles and a week of driving since. The is the only post I've found that goes into detail of misfire codes without any noticeable symptoms. I hope this can help at least one other person out there with the same issue, for those of you with rough idle, loss of power and other symptoms. Fix it now before you destroy your Cat and spend several thousands more! Good Luck!

Ended up solving the misfire issue, stalling while driving, and computer issues. Did so research and found out it was the crankshaft sensor. They usually only last for 75,000 miles and when I went to replace mine it fell apart. My 06 has 116,000 but I have no issues now.

Ok here's the skinny,you should have ngk plugs gapped at 44 thousandths, coil packs and injectors can be ordered for about $100 , if it's got a lifter tick change them , again maybe $60 and it's easy to do, run a compression test ,there's a bulletin on them ,valves go bad regularly, mine hit 150 on all, these engines must stay clean, replace 1 qt of oil with a qt of tranny fluid every other change and keep it changed regularly, then after all that and it still runs bad change the $20 crank sensor lol, then it will run great also on the newer ones that have staked in ujoints that are non replaceable u can get a Napa uj446 ,it's for a Nissan but it will work just gotta be a little ingenutive

So after all that the plenum gaskets were leaking because of the cats being clogged and carbon buildup on valves ,they make a valve cleaner you spray in the engine and a cat cleaner you add to the fuel

I have a 2003 Jeep Liberty 3.7. Runs great but randomly check engine light will flash and it starts acting like its gonna die but doesn't. Shut it off for awhile and start back up its fine. Sometimes light comes back on solid for awhile but runs fine. Code is misfire on cylinders 1 thru 6. Being told that plugs and coils look good. 2 different shops no diagnoses. Currently at a shop and they cant reproduce problem. Check engine light currently off. Any ideas?

I have a 2003 Jeep liberty, It started stalling at a stop once it warmed up, but not if you gave it gas, took it into the shop and the replaced the iac, ran good for about a week the the check engine light started flashing and accelerates slowly, when you press the gas the vehicle viberates, hooked up a code reader and it says cylinder 1 and 6 are misfiring, any ideas on what it is?

had multiple misfires. Cloged cat was causing rhe misfires. $200 fixed the problem with new replacements!

2012 liberty sport, did all the coils, plugs, wires etc 3 months ago, then a month later cylinder 5 misfire, Mopar (jeep), replaced #5 coils etc, then it happened a month later, service tech just called me and said after doing a more through investigation I need to replace the cylinder. ($4,000), it has 85,000 miles and I don't wanna spend that kind of monsy, any advice would be great.

Could be a crank shaft sensor or cam shaft sensor Causing the coils to misfire I am actually experiencing the same problems.. The 2012 is a V6 and only has 3 coils each coils fires 2 cylinders so if one goes down you lose 2 cylinders of power which will make the engine bog down or not run right..check your sensor a $35 repair is better than $4000..good luck

I have an 2003 jeep liberty and I had multiple random miss fire. Was so bad had to pull over after 8 miles turn the jeep off and back one due to power loss, I recently changed out all 4 o2 sensors and now I'm not having any problems, car is old and been changing out all sensor and the o2 ended up being problem never had code for it at all.