94 GPSE 3100 idle problem
 

my moms GP has a high idle(1500rpm) that comes and goes. when it comes it stays for a few days, throws a high idle code AND the ignition wont turn all the way to the OFF position..? then magically all will be fine...

i cleaned out the IAC but that didnt help. it doesnt appear to have a minimum idle screw. and the computer is reading a throttle angle of 1% whens it idleing high

vacuum leaks? The 3100s are notorious for having an intake manifold leak.

I'd suspect the TPS going bad if you don't find any vacuum leaks. Try watching the TPS values as you step on the pedal, and see if it increases smoothly.

you could also measure the voltage on the tps. should start at .5 volts and end at 5 volts wide open i believe.

cleaned out the EGR, wata mess! took it all apart and cleaned and lubbed up everything, took it for a test run and now the EGR is functioning, not setting off the SES light, and i can see it working on the scanner as i drive! now if only that ideling problem would go away! once it warmed up after cleaning the EGR it idled perfectly

There a cold start valve on that?

beats me? still idles too highhhhh