idling problems when engine warm

[marlon95]

when my engine warms up, i am having idling problems. the rpm will be unstable, will drop to 200rpm, then back to normal, than drop again, and eventually the engine will shut off. i just replaced my spark plugs and icm unit.
accelaration and driving is fine however (cold or warm enging), no misfiring, no loss of power whatsoever. no light are on in my dashboard, except Check Gauges, but that is when the engine shuts off after that unstable idling.
anyone any ideas?
thanks in advance!

[Jeff_in_Atl]

The first thing I would suggest is taking out the IAC and cleaning it and the port with carb cleaner. The IAC controls the air going into the engine at idle (Idle Air Control)

[marlon95]

thanks for your answer.
The car is 10 years old, the IAC has never been replaced, this solenoid/IAC gets worn out over time?/ in other words, do you think it's time to just replace the IAC?

[Joe 1320]

The first thing I would suggest is taking out the IAC and cleaning it and the port with carb cleaner. The IAC controls the air going into the engine at idle (Idle Air Control)

Don't use carb cleaner, use throttle body cleaner. It's has another benefit of being 02 sensor safe.

[marlon95]

thanxs Joe, i got your warning about throttle body cleaner just in time

[marlon95]

i took out the IAC valve, it was full of carbon, and i cleaned it with throttle body cleaner. the problem seems solved, but when i start the engine, the rpm will rise to 1500rpm, then after 1 or 2 second, fall back to 1000rpm. when i switch into Drive, it will drop to 800 rpm. sometimes during driving and coming to a stop, this will occur again. is this normal behaviour, or must i somehow reset the IAC valve?

[SteveH95Formula]

You should take your throttle body clean and clean the throttle body itself. Some times carbon will build up on the throttle plates.
At first keep the engine off and clean any visable build up by holding the throttle open by hand. Then use the TB cleaner a little while the engine is running should clean the rest of it.
You might have to up the throttle a bit to keep it from stalling.
Pretty simple but worth a try.

[Jeff_in_Atl]

That sounds about normal.