i have a 16v motor which runs like a top except for one small quirk. when i warm it up while driving after a few blocks, and push the clutch in say while coming to a stop at an intersection it drops in idle to like 200rpm. if i come to a complete stop after a few seconds it climbs back up to normal idle and runs perfect untill i turn it off. then if i restart it even after just shutting it down it will run fine for a couple of blocks then the low idle thing happens again untill i come to a complete stop. even if i roll to a slow speed with the clutch pedal in resume speed the problem will stay untill i come to a complete stop and wait a few seconds.

i've repaced the plugs, wires, rotor, cap, air filter, and pcv valve.

any ideas ?

thanks

TPS?  got a service manual?  mine would almost die at stop signs, hesitate when punching it, and the idle would waver a bit.  adjusted, wow what a difference.  just an idea, easy to adjust.

hmm, mine drops like 200rpm, maybe a bit less when i let the clutch out in neutral, probably cause of friction, but that doesnt help you unless thats what you meant to say
oh, come to think of it, my sidekick that i used to have did that, it was a 1989 8valve and i never found out what was wrong, but i'd leave it in gear til i hit around 1000rpm when decelerating and quickly save it and push the clutch in, the engine didnt seem to have the momentum to come crashing down into the 500rpm mark that way and it would idle fine
i actually enjoyed doing it towards the end

Andrew

TPS?  got a service manual?  mine would almost die at stop signs, hesitate when punching it, and the idle would waver a bit.  adjusted, wow what a difference.  just an idea, easy to adjust.

i got a haynes manual, i'll see if it mentions how to adjust the tps.

thanks

mine doesn't hesitate during acceleration, it's just that one problem i described.

sorry i jumped the gun there a bit.  the first thing i would check is for a vacuum leak.  get some spray carb cleaner, start the motor and spray it at the ends of various vacuum lines, if the idle changes there is your problem.

then maybe the ERG system and lastly the ISC sylinoid valve(which i have never done).  thats all i got, hope that helps.  you will need an Ohm meter to check the TPS and ISC the right way.  your Haynes manual should have all the Ohm specs, mine does.  i supose it could be a fuel system prob. or the idle stop plunger(ran by vacuum) but i have never done anything with those.  good luck.  

i don't think it's a vacuum leak. as after i come to a complete stop, wait a couple of seconds it recovers, and runs fine until i restart the engine then that cycle starts over again. once it recovers from the couple of seconds at a stop there is no more problem.

i was wondering if it could even be the o2 sensor ?

Sounds like a sensor problem, check the air temp sensor, and the coolant temp sensor, don't rely on the engine codes, it will only tell you if the part is in complete failure not on it's way out, I agree with the prevous post as well check your vaccuum lines.

Mac

doubt its an 02 sensor being that i had the same problem before and the 02 is still dead today w.o the problem

mine was simply a bit of water in the gas tank used some HEAT( however its spelled) and it went away

do a compression test my truck does the smae thing but idles really ruff, it turns out i have a low cylinder compression in one of my cylinders, time to replace my head, but i would check the compression this will tell you alot. and try to run soem methyol hydrate in the tank to elimidate any water traces in the gas

I have the exact same problem now with my 16v, and I swapped out the old airflow sensor, but the problem still exist.

I had a problem like this before, and had to replace my ECU. I'm just hoping that it's not the ECU again.

Zukk

I've had the same problem for years on my 4-door.

Not a big enough problem to chase...

I've had the same problem for years on my 4-door.

Not a big enough problem to chase...

i agree it's not a huge problem, but if someone in this group could pin it down from previous experience then i'd be happy. i'll eventually figure it out, the air temp sensor might be the first thing i check, it seems like a logical first step.