1993 Geo Storm rough idle

Ah, Yes, My 90 Geo Storm 2+2 does PRECISELY the same thing.

Ive had expert mechanics look at it, and everyones baffled.

First off, we pulled the valve cover, set the valve clearance, checked for stuck valves. Nothing. Clean as a whistle.

Then we tested the TPS, works to a T.

Then we swapped O2 Sensors, which helped, but didnt solve my problem.

We then adjusted Ignition timing, which also helped.

What I suggest doing, swap a new Idle Air Control valve in there, AND, flush the motor, I suggest seafoam.

THEN, clean the injectors. Even if it doesnt fix this problem, it will always help. =D

Hope I helped

Just got it outta the shop again. The IAC didnt help. The timing is still right, yet it still has this problem.

Ign timing seems to up itself when the AC is on, and it makes the idle smooth out. But when we advance the ign timing to where the AC knocks it up to, its no better.

Somewhere along the line, something engages with the AC button, along with the IAC racing, and the timing upping. Whatever THAT thing is. ITS the problem.