I have a new question, I have noticed when it rains, when I am at idle, it will drop down a bit, then go back to normal. It drives great, and still starts just like normal. I am trying to figure out if this is a bad sensor? I let it idle today when it wasn't raining and I couldn't get it to duplicate at all. Any ideas? Could it also be a vacuum leak somewhere?

Might also be an ignition issue (plugs or wires or coil).

_________________
Boost addict


The Fleet:
'93 SSEi - Twincharged + manual Build thread
'97 Camaro - Top swap
'05 STS - V8, AWD, her DD
'92 Trofeo - Fair weather DD
'99 Montana - top swap 3800
'04 Sierra 2500HD - LLY Duramax

Current project:
Something cool, trust me.

Upcoming projects:
'92 Bonneville SSE
'87 LeSabre T-type
'67 LeSabre

Gone to greener pastures:
'84 Sierra Classic - Twin turbo 3800
'97 LeSabre - Top swap

RIP:
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'93 SE - L67

Today I was driving, getting up to speed to about 50-55, and my car bucked and kept going, not sure if it's misfiring, and then all of a sudden I would get reduced power where I couldn't go past 20 or else it would buck and jerk, and then it would go back to normal. Not sure what is happening here, but I am bringing it over to my buds today and see if he can figure out the issue. No check engine light, but could this be bad plugs/wires/coil?

OK so update, I was driving through the mall parking lot on my lunch break, going about 15 MPH, and my car died on me, and its not starting back up. It will turn over, but not start the engine. I think you may be right about it being an ignition isue

Yep, definitely sounds ignition or fuel related. Try unplugging the maf sensor and see if it will start and run. If it does, there's you're problem. It also sounds like it could be a bad coil pack or icm. Does it tend to do this when it gets fully warmed up too? The icm and crank position sensor like to act up when it's warmed up, but the car acting up during rain has me thinking a bad coil or icm. I had a coil go bad, and it would only act up in the rain too. I diagnosed it by using a spray bottle full of water to mist the coils. The bad coil was arcing from the base. This is easier to do at night or in a dark environment to see the arcing.

_________________



Joseph

Current: 2013 Infiniti G37 Journey
1999 Infiniti G20T - Sold
1999 Buick Lesabre - Race Couch - gone but not forgotten

I too would first try unplugging the maf - when it rains, barometric pressure drops and a funky maf may not be able to compensate for the pressure change

it may also be an issue with the MAP sensor that wholly relies on barometric pressure = too easy to test - get scan tool that will pull map pressure - key on, engine off - record map reading - it should match barometric pressure with no engine pressure in manifold which is ambient pressure - consult weather site and get the barometric pressure - if there is a difference in pressures, the sensor is funky. for instance, if you are at sea level, you should get 1 atmosphere which is approx 14.5 psi. if your reading much less, you should be at higher altitude and the MAP is funky.

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

Ok so I realized that I had an ignition wire basically hanging off, I think it was #5 on the front. I popped it back in and it started up fine. I still have some weird issues here and there, and but seems to be running a hell of a lot better now. I still get some very small RPM movements when I am cruising 40-60 MPH, its like small shudders. Not sure if I have a check engine light. I just noticed that when I start my car, the engine light doesn't even come up, so there could be a clue there. I don't know how to change the check engine light bulb lol.

Throw a code scanner on it, and you will probably find out why the light isn't working.

_________________
~Randall~


1993 Buick Park Avenue - 197k - Some odds and ends done - Simply won't die
1994 Buick Regal - 78k - Bone stock - Always ready for a good kicking
1990 Oldsmobile 88 - Gone to a better place

Good idea, so I can just go to an Autozone and have them scan it? Usually they won't do it if the light isn't on

OK so I got my computer scanned, and it gave me the following codes:

P0440 - Evap system no flow during purge
P0341 - CMP sensor signal Range/performance
P1406 - EGR Valve Pintle position circuit malfunction

Hmm..so where do I start with this?

P0440 can be one of those stupid codes that is hard to track down, and has no real impact on performance usually. My money is on this being why the light was decommissioned, so that it would stop shining in the previous owners face.

I would make sure the codes are cleared, and then have it scanned again after a few days, to see which codes come back.

_________________
~Randall~


1993 Buick Park Avenue - 197k - Some odds and ends done - Simply won't die
1994 Buick Regal - 78k - Bone stock - Always ready for a good kicking
1990 Oldsmobile 88 - Gone to a better place

Thanks for the tip. I will get the codes cleared, and have them checked again. I know in the past the check engine light has worked before, but not sure why it would go out like that.

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

If you had a plug wire that was not connected, I would certainly either clean or replace that spark plug. That may be the problem. Also, with a plug wire not connected, that would most likely cause all of those codes. I'm surprised that you didn't get a code for the misfire though.

Well my check engine light doesn't work, so I really had no idea that I was throwing codes. On a hunch I had it checked out. I will definitely inspect the spark plug later when I get out of work.


I did recently fix an oil leak from the valve cover. I am afraid some dirt and oil got on the spark plug when the wires were hanging off. I am definitely going to look at it today.

This site has some good info about the codes and their possible causes. Some things can be relatively easy to fix, such as if the P0440 is fro a poorly sealed gas cap.
http://www.obd-codes.com/p0341
http://www.obd-codes.com/p0440
It doesn't have details on the but this site does, along with diagnostics to perform.
This page is linked from their 3.8L GM section, so it would seem that this info pertains to a number of GM engines.
http://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/egr-valve-tests-1
Also be sure to take a careful look at the ribbed EGR pipe, as they sometimes crack and cause problems.

Okay...soo. Update. Finally got this figured out. Apparently a previous owner before myself did a poor wiring job from the ignition control module. It was routed in such a way that it was dangerously close to the exhaust manifold. So in turn what had end up happening is that a wire was touching the manifold and causing it to short out, which caused the crazy sputtering/missing, and eventually just stalled out until cooled off. I could only drive it for about 15 miles or so until it was warming up. Finally got that repaired, and it runs amazing now.

And it only did this when it rained?

Glad you found the issue.