I have a rough idle when the engine is warm. I've cleaned out the IACV thingy on the side of the inlet manifold and it hasn't improved.

When I unclip the wiring to the IACV the idle speed raises to 1200 and steadily stays there, effectively solving the rough idle.

Any idea on why this is happening? Is it ok to leave the car running with this disconnected?


I'm supercharged with AEM standalone.




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You can try cleaning the iacv. I think your idle needs tuning though.

 

Thanks for your reply, i had already cleaned the IACV. It's totally gleaming inside and it has been tuned by a Jeff Evans.

What I was asking is -

What does it mean if when the IACV is unplugged the idle smooths out and is it ok to run without the IACV connected?


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You can, but what you're doing is causing the IACV servo to open wide open. This basically causes a vacuum leak.

 

it could be caused by a gasket leak. Such as the intake manifold gasket. I had a similar problem, my gaset was leaking it runner three as was causing a bad idle and a misfire. Also making the map sensor read out of wack. Not saying its it but you could spray some brake cleaner on the gasket while its running as see if you see any bubbles.. maybe the throttle body gasket as well.