I just swapped an S5 turbo into my 91. When it's really cold, the idle is solid at 2k rpms. Then while it's warming up + sometimes when its been warm for a long time, the idle will bounce with the clutch in in neutral.

Is my ACT pressure plate causing the engine idle to bounce because it's extra stiff? Only other mods are apexi dual N1 catback, apexi air filter + a boost gauge. I don't think it's a vacuum leak because I literally drove a block, had the idle bounce in N then drove another block + then it was fine. I'm puzzled

 

Vacuum leak seem like a more likely scenario...

 

I'm pretty sure that a vacuum leak would be a constant thing + not something that would change with the clutch in or out.


Anyone else?


ZOMFG post 777

 

I'd check the BAC and the TPS, both of which have more to do with idle than the clutch.

 

quick answer, no.