1999 K1500 Suburban, 5.7L, 141, 500 miles

Without other parameters, I would start with fuel pressure. You are looking for 60-65psi at the test port KOEO and around 55 -60 psi while running. With a Tech2 or modis I could tell you what cylinder is misfiring, or if you are out of time. Check your fuel pressure, trace your ignition wires next making shure they are good, even check you plugs, cap and rotor. A cracked plug will cause a bad misfire, but the cap and rotor are common for corrosion, and will fix most running issues.

Did you pull the distributor cap to see if it has skipped a set of gear teeth where the distributor is no longer pointing at #1 during its correct sequence in the firing order ? That would cause a lack of power and backfires. Check timing before going further and then look for vacuum leaks.

New coilpak installed in January 2013, 8 new plugs installed in December 2012, new wires, cap & rotor in summer 2011 @ 120,000 miles. #4 & #5 injectors threw a code, but I don't know what it said- but the internal fuel injector cleaning was done (not through the gas tank). No power still. The mechanic did not pull the distributor cap, but did check that all plugs were installed in the right sequence- they were. I am not a mechanic, but I can suggest these things to him. He thought it could be a solenoid in the transmission OR a plugged catalytic converter?

IF it is the solenoid- in this vehicle is the solenoid on the transmission internal or external?

I prefer to go by two rules when working on anything - #1 - KISS (keep it simple stupid) Check the distributor to make sure it hasn't skipped a tooth and #2 - CYA (cover your a--) Have the catalytic converter replaced. Since it does have 141K miles on I would do both.

Thank you! I am sure hoping it is the CC instead of a transmission issue. I will ask him to check the distributor. His other thought was CC.... Do you know if the CC on this vehicle has to be welded or can it be replaced using clamps? My mechanic can do it in my garage if it does not need to be welded....

I doubt it is the transmission as there would be other signs. Aftermarket catalytic converters can be purchased at an auto parts store and you want to use 2 or 3 inch wide "lap joint" band clamps. Look up Summit Racing "Walker Lap-Joint Band Clamps 33276" so you know what to look for a your local auto parts store or order from Summit directly. This would be just a cut and replace installation with a reciprocating saw or hack saw and a few wrenches.

Thank you so much! The Walker Aluminized Band Clamp for 2.5 inch is $8.49 and 3" is $9.99 at Advance. The following are all exact fits for my truck: Walker Universal Catalytic Converter is $129.99, the Walker Catalytic Converter - Ultra Direct Fit is $359.99 and the Walker Cal-Cat OBDII Universal Converter is $167.99. Which should I use?

When it comes to "band clamp" use, you want to make sure your cuts are close enough so that there is only 1/16" or 1/8" space between the two pieces of metal (the exhaust pipes) before the clamps go on. The clamps are designed to "clamp" the pieces of exhaust pipe together AND keep exhaust pressure from blowing the joint apart later. The 2.5" clamps should be enough if done correctly. Measure your pipes to get the right size BEFORE you go to the auto parts store. When it comes to which Converter to use, my thought would be "Where do you live ?". The "Walker Universal" is designed for carburated autos that need Cat Converters, the "Walker Cal-Cat OBD II sounds like its an aftermarket replacement for EFI autos that have to be OBD II compliant and the "Ultra Direct Fit" is what you would buy if you went to your Chevy dealer. I think the "Cal-Cat OBD II" would work for you if your looking to get back on the road and aren't worried about direct replacement parts.

Let me know how you made out after the CC change over.

Thanks for checking! Starting with new distributor cap and rotor, if no change will have the CC done. Nobody was available to do anything yesterday so the first step will be done today! I live in NH so does that change your thoughts on using the third option for the CC?

I will have him change CC regardless, but need to start with the simpler "fix"

Here's a pretty good article on the causes and how to troubleshoot and fix a misfire. http://www.autotap.com/techlibrary/diagnosing_misfires.asp

Your in New Hampshire, I think the "Cal-Cat OBD II at 167.99" sounds good.

Thank you, Bradley! Good info in the link, I will send to my mechanic! I'm happy to hear the mid price CC is the one to buy! Thank you!

The cap and rotor were replaced, but now it's stuck in 4LO???

jcmnh - The truck is stuck in 4Lo ?, Is this another issue you are having with the Suburban ? Did you try rocking the truck (while shut off) to see if the transfer case will shift into 4Hi, while the transmission is in Neutral ?

I have never had my truck in 4Lo, only in 4Hi during snowstorms. I just have a button to push for 4 wheel drive. Never had a problem with 4 wheel drive in the10 years since I had the truck. He said he got more power after the cap and rotor was installed, but it's stuck in 4Lo.... I am not with my vehicle now, I asked if he drove it in reverse for 25- 30 feet to see if it would come out like with older vehicles that do not have the button. I asked him to check the fluid level in the transfer case and I don't know what it entails to check the actuator.

Depending on who built the transfer case switch, it could be electric operated, vacuum operated or both. Have the mechanic check the 4x4 activation system by starting at the transfer case, since that area is more susceptible to harsh weather damage.

I have never done anything to the transfer case switch, I would imagine it is factory? Whatever that means for this truck.... Why would this all of a sudden happen when there has never been an issue before? It seems a little odd?

Its obvious someone has played with the switch for no good reason. If your looking to fix a timing issue or exhaust leak, you have no reason to touch the 4x4 activation switch at all. It probably is the original equipment switch both in the dash and on the transfer case, BUT my first thought would be - "Why is my mechanic touching the 4x4 activation switch inside the car, when the issue is out under the hood and underneath the car ?" Definitely odd, but maybe he has a good explanation and you should ask him with an "open mind" before you let your mind wander too far down the wrong path. Bit of Advice - If he tries to tell you the 4Lo system was activated, you know its bull. The 4Lo system would allow you to go much over 35MPH if you got to 35MPH, and the tires would be torn up horribly very quickly on dry black tar in 4Lo.

Correction - The 4Lo system would not allow you to go much over 35 MPH if you got to 35 MPH, due to the shaking and vibrations coming up thru the steering wheel, and the tires would be torn up horribly quickly on dry black tar in 4Lo.

I was not driving in 4Lo when when all these issues began, I have never put my vehicle in 4Lo in the ten years I have had it and I have never had it in 4Hi unless we were having a storm so I am not sure why it is in 4Lo now. Is there a way to disconnect the 4 wheel drive function that cold temporarily fix this specific issue?

Not that I know of, unless disconnecting it might help.

A new switch was put in for the 4 wheel drive and it still will not come out of 4Lo. It was rocked while in neutral and shut off, it was driven in reverse for 20-30 feet and even meineke could not get it out.... Any thoughts? .... The way it was driving would make sense that it was in 4Lo, but I only went about 20-30 miles, no faster then 30mph before I stopped driving altogether, so the mechanic didn't touch the switch.

Can your mechanic disconnect the electrical switch from the harness, then find out what wires would put the transfer case into 4Hi or 2Hi and then add a shot of "fused 12 volts" to "jump the circuit" with fused jumper wires to try and get it out of 4Lo? Sorry but this is why I only by 4x4's with shift handles.

Apparently electrical issues are a real pain... I sent this suggestion to my mechanic... Is it possible to simply remove the 4WD fuse under the hood with no repercussions? I did it for my ABS and no other issues were caused by doing that... Thank you for your continued advice.

I would obviously fix the 4WD before winter, but I need a vehicle to drive now...,

I don't know, but I would think if you drove the truck without the fuse in the OBD II will read a code basically saying "the fuse is blown". I would say to talk with a regular GM dealer before you go down the road and find out the transfer case is damaged worse.