Cause Of Misfire.

[Nesquick]

Hey guys,

I have a high idle issue / SLIGHT misfire.

Idle issue first:
The AAC valve works, when I unscrew it, the idle goes up. When I screw it in, it will go down but stop at ~1500 RPM. When I cause a vacuum leak on purpose, it goes down to ~950 RPM. When I retard the ign timing on my AEM S2, the idle goes down too.
Any other ideas?

Misfire:
The car will idle (high) for a few seconds. Then there will be a little misfire for a second or two then back to normal for a bit. I replaced the coilpacks with yellowjackets and replaced the coilpack harness with one from Wiring Specialists. Replaced spark plugs as well with BKR7E plugs.

Could IAT sensor be the cause of some of this?

[ezb57e]

No.

[Nesquick]

Any ideas what it could be? Tune?

[ezb57e]

I would concentrate my efforts on getting the idle down to where it should be.
Either the IACV is stuck open, the throttle plate is open too much, or there is some other source of air, like the PCV system, brake booster, who knows.
With engine idling lower, the misfire may be more obvious and more easily tracked down.

[RRRRB]

air regulator stuck open?