IAC valve/TB cleaning results.....
 

ok, removed and cleaned the IAC valve and throttlebody. my symptoms were rough idle and sometimes misfire code on #1 cylinder. after car gets warmed up, everything is fine. no trouble in weather from 35degF or so +, or if i let the car warm up for a few minutes (which i've been doing the last few months.)

i started the car up today after work, and drove straight out of the lot, and up the big hill i use to go home. it sputtered a LITTLE BIT on top of the hill, but no misfire code! if i had done this previously with no warm up, it would have been bucking like crazy and most definitely have kicked a code.

i'm guessing the ECU is still trying to find the idle after the thorough cleaning, so maybe i'm a little hasty in posting results. i'll post results in a few days when the ECU can get itself calmed down a bit. there's definitely a difference, though! :)

I'm glad you're still posting about this..
 

I have the exact same problem. When I first seached the achives I read your posts and said "Damn I bought this guys car". I live in Pittsburgh and have an eboby '97.

I get a misfire cylinder 5 code randomly. Car stumbles as I drive while warming up then flashes and stores the CEL. Didn't start till winter I bought it this summer.

I was thinking either slow to close auxiliary air valve or intermittent coolant sensor but dirty idle stabilizer is possible. I don't know why a dirty stabilizer would only casue problems thru warm up. Like you never a problem warm.

Bearer of bad news
 

Idle air controllers, etc. do not cause misfires at any speed or load. Period.

I'm with Beav on this one. If you have a misfire, I would look at the plugs and coils.

normally, i would agree, but.....

i had my plugs and the #1 coil replaced (i would get cylinder #1 misfire code), and no change in the symptoms.

the only time it would misfire is when it was cold (and i mean, "sitting all day in below 30deg weather cold"), and the idle was goofy. it would stay at 1500rpms for much longer than it does now after the cleaning. when i drove it out of the lot Friday after sitting in the cold, it did sputter a little, but definitely not like it used to (and no code, either). like i said, i think the ECU was still working things out. now, a few days later, its much smoother, so the final test will be tomorrow, when it sits in the lot all day while i'm at work.

i should also mention that the "notchy" gas pedal (feels like there's only 3 positions on the pedal, as opposed to an "analog" feel) was gone this morning. :) i got that in pretty much all weather for the first minute of driving.

again, i only had this problem in the winter and within the first 5 minutes of driving on a cold start without warming the car up for a few minutes.

for anyone else with the same symptoms, try this before removing the throttlebody and IAC valve:

find the big hose that goes from the rear of the plastic housing that connects to the TB (it is held in place at the rear by a clip that is part of the black plastic housing.)
follow the hose under the TB to where it connects to the IAC valve. if you can disconnect it from the IAC (long-nose pliers might help to get the sqeeze-clamp off), you can then spray some cleaner into the IAC without removing the whole mess. might be worth a try, before taking everything apart for a proper cleaning. i used Valvoline Synthetic Carb, Choke and Throttlebody Cleaner, FWIW.

Then something else is causing your misfire. I just have a very, very hard time believing that the throttle body or IAC could cause it. I'm glad your 'notchy' (!) accelerator is fixed, but I wouldn't expect the misfire to go away after cleaning the throttle body and IAC. I'd look elsewhere in the ignition system.