lumpy idle

[low_vr4]

Hi guys, just had my rocker gaskets done and now my car has a really lumpy idle, its almost like it's idling too low. Any ideas?

In b4 "should of done it yourself" and "you got ripped off"

[Subaru ETA]

Sounds like either it has an air leak, or the battery was disconnected and needs to relearn it idle point

[low_vr4]

Ok I've reset the ecu again, it starts idling at about 1500rpm then drops to about 400rpm, I'll leave it idling for abit longer

[Wodjno]

Shouldn't be an issue with idle learning as stepper motor constantly resets itself to adjust idle.
More probable that its an air leak, vac pipe off?

[low_vr4]

What should vacuum be at idle?

[SEAN-NZ]

about -10psi i think, vac pipes not connected to inlet manifold will cause a terrible idle, almost wanting to stall constantly

[mattnz]

Should be -20inHg

[low_vr4]

From memory it was always 20inhg, now its still at around 12inhg?

[SEAN-NZ]

prob a vac line off the inlet manifold, maybe the brake booster?

[Adam.Findlay]

there is a few vac lines it could be. there are two that connect to the bottom of the inlet runners in the valley between the heads. one on the very cambelt side of the engine which connects to the power steering line. and another one which connects to the pcv valve on the front rocker cover.
also the two on the back of the plenum. one for the wastegate rail and the other for the brake booster.

[wintertidenz]

Also check all the intercooler pipework if you've had that off - you may have missed off a vacuum line or something may be loose.