Oil pressure 'guage' going up and down while driving

ac fan not likely related. possible faulty blower motor or blower resistor assembly failure there. Dropping to 0 and back up is likely either an intermittent wiring problem in the oil sending unit or the sending unit itself. not likely to be engine related unless you hear bearing noises or have metal in your engine oil. also once oil pressure goes low mechanically it usually never comes back to normal.

Has anyone found a fix for this? Please help

Try replacing the oil pressure switch. $18 @ OReilleys

My oil pressure gauge goes to 0 when at idle but only after I drive for ten min no other warning lights come on oil level is good going to change the oil and filter and pressure switch Hope this Fix's the problem.

i just did the oil pressure switch on my 2002 trailblazer and it didnt fix the issue. any one got any more ideas?

Your instrument cluster is going out oreily has a replacement 279.95 th you have to purchase the cluster with a core charge 300.00 install the unit and return the core this fixed the problem your describing sorry to tell you that.

Instrument cluster is

My trailblazer just started doing this today. Can the person who posted the original question comment on what was the final outcome of your problem. What was the fix?

It’s the Variable timing solenoid.... My trailblazer was doing the exact same thing, took it to Midas and the fixed it.. cost over $200 with oil change and stuff. But it’s been fine ever since.. The solenoid gets clogged, (that’s the pressure dropping)and doesn’t let proper amount of oil thru.. You can fix it yourself if you’re good with working on cars.. It’s located on the top, front left side of engine about power steering pump. (You can youtube it)

I found the oil pressure gauge is NOT an actual oil pressure gauge. When the sending unit reaches 4 1/2 pounds of pressure, it sends a signal to a computer. That computer then monitors other engine stuff like speed, RPMs, Temperature and simulates an oil pressure. When things start happening here, the oil pressure can be just fine, but the stupid gauge will go up and down for no reason. Good luck finding a fix.

The oil pressure problem on Trailblazers is caused by sludge buildup on vvt selonoid (easy fix), or clogged oil pickup tube(OPT), or both. Cleaning opt require removing oil pan which is super difficult. People had success with draining the oil. Pour in 3 qts of Gunk parts cleaner thru dipstick tube. Let it soak for 2-3 days. Do NOT run engine. Shake car every few hours. That will dissolve some of the sludge. Drain all fluid. Add new synthetic oil. Retest truck. Drive for 15 min, then see oil presse while idle at stops.

How do you know it is a guage problem versus an oil pump problem. I do have a 2003 TB with 288K miles and have instrument cluster problems in the past so I pass it off as that but what are symptons of the oil pump going out?

Just fix ours oil pressure dropped at stop. So oil change,oil pressure switch. and cleaned throttle body and intake housing itself (the hose from valve cover to intake stopped up and tit it plugs into was nasty inside hosed out with rest of intake cleaner) and not much on engine oil flush but did a 5 min treatment but everything works great now hope this helps

The vehicle only has 78,000 miles on it, and no sludge buildup. Still trying to figure this out.

My pressure would drop at idle and my truck would almost cut off. Then would idle back up and my pressure would go back up. But runs fine. Just at idle it does this. Hasn't completely cut off. Not yet antways.

I dropped my 04 Trailblazer off at the mechanics on Friday for this to be fixed. Replaced the sensor and on the way home it did the same thing so dropped it off again Monday morning. The instrument cluster was "refurbished" a year ago. My suggestion, don't buy GM!

This is a common problem with Trailblazers with probably 150k+ miles. I bot my truck second hand. It did the same thing. Replaced the pressure sensor, VVT solenoid, switched to Synthetic, tried many engine flush oil. The cause is sludge buildup clogging the Oil Pick Tube. To clean it, u must remove the oil pan which is super expensive and complex. I even tried filling pan with Chem-dip for a week. Now, I'm thinking of drilling a hole in the pan right under the oil tube. Use a pick tool to clear the gunk, then tab in a new oil plug. Crazy thought, huh?!

Does anyone know if this light will be a problem in passing an inspection?

My 2002 does it when IAM hitting the gas? Any ideas and not all the time just mostly when cold

Update to my 05 TB Low Oil pressure problem. The soaking of Oil-pickup-tube(OPT) in parts cleaner did not make a huge difference, but may have helped loosen the clogged sludge a bit. Next, I decided to try AUTO-RX. I changed oil to regular, and used 2 bottles of Autorx. Drove the car for 2k miles. When I drained the oil, it came out very thick & black. I opened the oil filter with snippets, and I was amazed with amount of sludge trapped. I noticed the 1st improvement at around 1300 miles into 1st treatment. I recall that day, I drove for 30 mins, came to a stop light, and the engine kept humming with oil pressure staying above the middle mark. I also noticed when pressing on gas while on highway, the pressure indicator went up high (like 2/3 of way on gauge) which I haven't seen before. At that moment, I realized the OPT was starting to open up. After the 1st 2k miles, I changed oil again, and used 1 bottle this time. This stuff seems to work best with regular conventional oil (not Synthetic). Its very important to follow the instructions. That saved my truck from the junk yard.

I have a 2004 Chevy Trailblazer I changed out the crank sensor and now it's idling rough and my oil pressure keeps going down to zero if I change the oil and the oil pump switch will that fix my problem

I have a 2004 Chevy Trailblazer I changed out the crank sensor and now it's running really rough and my oil pressure keeps going down to zero when it's idling so do I need to change out my oil pressure sensor

No. The oil pressure gauge has NOTHING to do with the oil pressure. I actually just fixed mine today. It is the cluster motors that are going out and causing the swing in pressure.

I work at oreilly and by experience it can be 2 things. Yes possibly the instrument cluster, however, the majority of the time is your VVT solenoid. I believe its OBD code P0014. Price is about $90 for the part and yes YouTube has videos in how to DYI. Really easy!!

Pressure sensor, pressure switch, new gauge, change ur oil hell even just the filter if all else fails oil pump or cluster are the 2 you should save for last as they are the more speedy items good luck all

FYI on the oil pressure sender and gauge. The sender is an on off switch that is normally "closed"/connected. When 4.5psi of oil pressure is present the switch "opens"/disconnects and the pcm knows to calculate its pressure reading from engine rpm, coolant temp, ambient temp, etc. By disconnecting the oil pressure sender you are "opening"/disconnecting the circuit and the pcm thinks there is oil pressure. This could be a way for some of you part changers to eliminate changing out a instrument cluster when not needed. Once again the oil pressure sender located by the oil filter is simply on or off and the pcm calculated the rest. Unplug it to "bypass" the sender.

Don't use the FRAM filter, and you'll be fine. I had a problem with low oil pressure. I changed everything I could. Eventually the problem was solved only when I replaced the FRAM filter with one from ACDelco.