rough idle when warm

[Ganyon]

Alright my 2nd gen guys. My buddy has a 90 DA automatic. The car idles fine when its cold, but once it gets to normal operating temperature it starts idling rough. It idles about 450 rpms, but the needle moves up and down between 500 and I would say about 350 rpms.

I suggested that it could possibly be the IACV, but was wondering what else it could be.

 

[rexpepper123]

clean the Fast Idle Thermo Valve? low coolant?

 

[Ganyon]

I'll add that to the list too. The car has 235k on it and its all original.

 

[yetti]

Clean iacv & fitv. Also tighten that little screw in the fitv if need. If idle is still rough you can try changing o2 sensor, reset the timing. Hope you get it fixed. Good luck. =)

 

[Ganyon]

He mentioned the o2 sensor, but I said we'll try cleaning the other things first. Its cheaper then an o2 sensor.

 

[djzachtyler]

o2 sensor on a DA is only like 25 bucks man..

Being that the issue is more present when your car is warmed up I'd lean that direction..

 

[Ganyon]

I'll let him know.