Idle Bounce

[ars14]

Sorry guys. but I did try a few searches for this,

the idle seems to bounce from 500 to 750 and back when I stop at idle.?

It goes away when the AC is on.

anyway I have to order some valve gaskets

Andy

[wiscon_mark]

I have this happen every once in a while...I rev the engine a bit, and it goes away.

sign of a problem to come???

[AWD_addict]

I also have idle bounce.
Usually stops after driving the car for a little bit.

[scottzg]

IAC valve.

[wiscon_mark]

scott, you think mine is going? It only does this once in a while...

I'll run a search in the meantime

[CoreyMN]

I am also having troubles with an idle bounce on my '92 Legacy SS (auto). This happens when the engine is warm, but hasn't been running real long. When I stop at a traffic light the engine will idle fine for 10-15 seconds or so, then will idle down and almost die, but will then start to lope. I also have a problem with a lack of power when ran cold. Even when I'm boosting at around 9psi, there will be a significant lack of power. After I've driven for around 15 minutes, the power will return. I don't know if the two problems are related.
I've replaced a TPS that was out of tolerance, but there was no real noticeable difference. I was thinking maybe the bypass air solenoid valve because it seems to be on the same 12V supply as the wastegate solenoid valve that I am having problems with (boost drops to ~5psi, then back to ~9psi).
Does anyone have an idea of what to check?

[Legacy777]

The temp thing may be due to the coolant temp sensor not being good.

They're pretty cheap 20 bucks or so. I'd go ahead and replace it.

[Natoe]

my friends DSM does this too.. just be glad that yours doesnt go between 1000 and 1500 like his... we think its his IAC as well