well i just got my engine rebuild. and now my idle jumps from 1100 down 2 800rpms when i am at a light. and that happends when i let go of the gas at every light. so at one light it will be 1100 then the other will 800rpms. so do i just wait for the engine 2 break in or is there something wrong all ready?

 

sounds like a CAS or tps out of adjustment. my first thought is recheck those.

 

thanks will do.

 

Also check the boost sensor. i had the same problem and then noticed that it was off. check for any other vacuum leaks whlie ur at it.

 

If your car is warmed up, but you still have an idle that sits different RPMs after you let off the gas pedal, your throttle cable is probably just a bit too tight. See if you can pull the pedal back towards you and drop the idle speed at all.

Just don't make it too loose or you won't be able open the throttle all the way anymore. Backing it off a couple threads should be enough.

If it's a rough idle that jumps around without you doing anything, then yes, look for vacuum leaks and test the TPS for proper resistance values at all throttle positions.