I have an idle problem in my 94 wagon. The idle was way too low.
So low that the oil light started to flash when the engine warmed
up, now that it's above 40 degrees here in chicago. Fooling around
with things last week, I bumped, slightly, the throttle stop screw
at the throttle body and readjusted the throttle position switch.
voila, engine idle at 750 problem solved? No, not really.
The idle is now fine when cold, right at 750 whether in gear or not.
But as the engine warms up the idle surges up to 2000 when not
in gear. Then suddenly drops back to 1500, then builds speed again. In
gear, the idle is fine, though maybe now at 900, but the car never feels
like it wants to pull up to a speed that 2000 rpm would require. What gives.
The car has 140k miles, but I had to replace the engine at 98,000 miles.
Since then the idle has always been annoyingly rough, but serviceable.

Anyone have any ideas?