High idle, engine loses power, bucks sometimes....

[LuckyRJ]

Ok first off, I have a 2000 SL1, SOHC, manual.

I had Auto Zone run the codes. They came up with:

0122
TPS/Pedal Position
Sensor A Circuit Low Input

Ok so its a dealer only item. I get the 40 dollar part, dissconnect battery, install myself. I start the car up... same thing. High idle and engine loses power, sometimes bucks and wants to stall. Backfires occassionally, too.

I go back to Auto Zone, they reset the code. Immediately, the SES light comes back on. (It's been on for almost 2 months now.)

Ok now I'm getting aggravated. It's very hard to drive with the car like this. Also, I just had the transaxle and clutch replace about 3 weeks ago. The car did NONE of this before all that was replaced. The SES light was on before that, though.

The mechanic that did the tranny/clutch, said something about the IAC being bad. I told him don't worry about it. I'm going to replace the IAC if it isn't too expensive. If this turns out to be something stupid like a broken plug, then I will feel very stupid. Wires are virtually brand new.

Thanks in advance for any ideas/suggestions/help.

[Dennyav]

Hi
We had the idle air selenoid replaced because of high idle when engine was warm. It's the second time it's been replaced. It might be part of the problem.

[LuckyRJ]

and what is that.... where is that??

[sierrap615]

idle air control = IAC

your engine has a known problem of leaking intake manifold gaskets, near the #1 intake runner. spraying some carb and choke cleaner in that area will confirm the problem, as the idle should briefly drop. this typicilly results in a missfire and high idle codes, but i can imagine a TPS code is possible.

[LuckyRJ]

Thats really REALLY wierd that this problem should occur after having a mechanic replace the transaxle............

SES light has been on for quite some time, but the engine never had these problems until after it was in the garage.

So, I went and bought some carb/choke cleaner. I will spray this area you are refferring to, but the weather around here seriously needs to be better before I do that (I don't have a garage).

Thnx for advice.

P.S. (EDIT): When you say #1 runner, are you refferring to the #1 cylinder fuel injector port?

[sierrap615]

you are right about the runner. but seeing the transalxe replaced adds another little twist to it. inspect the underhood wiring for any damaged/pinched wires. recheck the code before proceeding past that.

[LuckyRJ]

Ok sprayed the hell outta the engine and everything else with carb cleaner. Nothing. The IAC fell apart in my hands when I took it out, so I replaced it. Started the engine and it ROARED over 4000 rpm and stayed there. I checked all the vaccuum lines I could find and they all seemed ok. So then I sprayed carb cleaner directly into the throttle body, and only then did the rpm's go down to about 900. Well that makes sense. Flood the air intake with liquid and the car can't breathe. Finally, went to Auto Zone, and had the codes ran. Throttle Position Sensor and IAC both came up. GEE..... Those are the two sensors I JUST REPLACED. My girlfriend and I closely inspected as much wiring as we could and all that seemed in good condition. Also, left the battery off while replacing each sensor. Auto Zone cleared the codes and the SES light came right back on upon starting the car. The idle is now at 3k. The idle didnt show any hint of dropping while spraying the intake manifold gasket area, soooo I am assuming that either the IAC got stuck somehow, or I have a major vaccuum leak. ECTS was also replaced (put the brass one in) earlier this summer. ANY suggestions...??

[LuckyRJ]

BUMP and THRASH to this thread. Problem Found!

It wasn't a vaccuum leak, nor a sensor, nor a gasket.

The PCM had a pin bent, which was shorting against another pin and throwing false codes and the high idle.

I'm letting them fix this. I'm through messing under the hood.