reeddy

Help! I can't figure this problem out. I'll explain the problem, symptoms/obervations and what I've done to try and fix the problem:


Problem:
My 95 PF (SE) has hesitation/idling problems when it is cold outside. I noticed the problem starting in early fall, as the mornings got cooler. The truck starts fine, but in the morning, if I jump right in and try to go, the truck hesitates when I put it in gear and give it gas. If I come to a stop sign, the engine dies. I restart it, and have a hard time getting away from the stop sign. I have to put it in neutral, give it a lot of gas and put it into gear (auto trans). While I'm moving, if I try to accelerate, I depress the gas pedal about half-way, and the engine does one of two things....nothing at all, or hesitates and accelerates a little then drops off to a steady rpm. Once the engine is warm, all problems go away. Or, if it is warm outside in the morning, there is no problem. Now that nights are getting cooler, I have the same problem with the truck leaving work.

What I've done so far:
It had been a while since I had changed the plugs and the fuel filter, so I did that. I also changed the PCV valve. No effect on performance. My next thought was the oxygen sensor. Before I did that tho, I took the throttle body off and made sure it was working ok. I couldn't believe the gunk on the inside (have 110k miles on the truck). Ever since I owned the truck, something on the gas pedal seemed to be sticking....I'd push down on it a little and feel a "release"...you couldn't ease into acceleration. Well, duh, there was so much gunk on the throttle valve that it was sticking and I had to unstick it every time I pushed down on the gas pedal. I cleaned it with carb cleaner and it's as good as new. Seeing all the gunk, I decided to SeaFoam my intake before changing the O2 sensor. Wow, what a difference. I noticed an immediate increase in performance as far as acceleration and smoothness of the engine. It didn't help the cold weather problems tho. Neither did changing the O2 sensor. I did disconnect the battery and left it disconnected overnight. When I ran the truck the next morning (it was cool enough where I should've had the problem) it ran fine. However, when I tried to come home from work, I had the problem again. I figured disconnecting the battery would clear out the computer, and thought I was right when the truck ran ok in the morning, but was surprised when the problem came right back at night. I have since tried to look at the error codes in Mode III and Mode V. I get 55 in Mode III (no stored error codes), and no flashes in Mode V. I was suspecting the mass air flow sensor, and was surprised with no Mode V error codes while I was driving around with a stalling engine. Also kind of surprising there are no stored error codes after the problems occur, as it definitely seems like it is a fuel/air management issue. Could the ECU be bad?

At this point, I have no clue what this could be. Anyone have any ideas? I really need to get this fixed, as I can't stand cramming into our "spare" car. (Anyone wanna buy a 2001 Grand Am GT?)

Thanks,
Ron

alexn103

i think if there was some kind of "guest" login people would have their questions answered a lot more often. these posts are found through google but not everyone is registered on these forums and a lot of people who do know the answer are discouraged from answering because of the registration process. it may be a quick 2 minute process but it adds up when you're talking about hundreds of forums. the process then becomes a nuisance and in return people who need help aren't being helped by people with the proper knowledge.

with that said, i am having the same problem with my honda civic and have not solved the issue either. i changed my oil, spark plug, and air filter but of course that did not solve the issue. since those were regular maintenance costs, i feel comfortable paying for it even if it does not fix the problem. i won't however, start paying for things that might not need to get replaced just to find the problem. so what i did was research as much as i can regarding the problem before putting any more money into it. the possible problems i have found are related to:

Throttle Position Sensor (TPS)
Idle Air Control (IAC)
Coolant Temperature Sensor (CTS or ECT)

I have not tested any of these for failure yet but I will be doing so over the next week. Some guy w/ a Tundra posted that he fixed his problem by cleaning out the Mass Air Flow sensor (MAF) which you are going to try next. that may fix the problem for you, but my 1993 Honda Civic does not come with a MAF.

Good luck,
ALex

alexn103

i noticed after posting that your post is from 2004. if you happened to have fix the problem please let me know what it was for you.

thanks,
alex