Hello,

 

'90 Legacy AWD Automatic N/A 2.2 - 151K

 

When engine is warm and I restart, the RPM bounces between 500 and 1000 for about 15 seconds, and then settles down.

 

Recently started getting slight stumble/hesitation when engine's cold and I accelerate.

 

 

Runs great otherwise and MPG is 22/28.

 

Recent new plugs, Subie (!) wires, and O2 sensor....and the bouncing RPM did it b4 any of this was changed, too.

 

...I'm thinking IAC or temp sensor??

 

Thanks

no check engine light?

 

not sure how the EJ idle controls work but if it's anything like the older gen stuff, just remove the idle air control valve and clean it out really good.

 

also - check for vaccuum leaks at all hoses. spraying of starter fluid i believe is the preferred method - spray around hoses and junctures, clamps, any leak will suck in the fluid and cause the engine to change idling abruptly.

No CEL...but need to check/pull codes....Cleaning the IAC was on my 'to do' list.....maybe just sooner than later.

 

Thanks Gary

Get some Sea Foam and pour it in the 1" hose going to the IAC. Let it soak a bit and then start the car. You can block most of the hose and let a little more Sea Foam be pulled through as it runs.