Constantly adjusting the idle... ???

[Jason91GM]

i have an issue with my 91.. its got a rough and sometimes erratic idle, and a mis fire when under a load... and it seems like i have to turn my idle up all the time... like it slowly drops down lower. engine light comes on rarely, cant check the codes cause my plug doesnt put out a signal. ive done a tune up of course, didnt help. any ideas? thanks guys

[Mercracer]

IAC

[Jason91GM]

you think thats the only possibility? i just dont wanna go changing $500 worth of electronics to find the problem. im going to carburator with the HO swap in a couple months, but the gas milage is KILLING me at 6mpg right now! thanks

[Mercracer]

I don't think that it would or even could be causing all of your problems.
Why does the plug not work?

[Jason91GM]

i have no idea. i went to Autozone and they hooked up the lil code puller and the plug had no power. so im going at this blind, ya know?

[Mercracer]

Ask for someone else to make sure it was checked correctly at Autozone, or go to a real shop and get it tested.

[Lincolnmania]

the screw is a throttle stop screw, not an idle screw........first clean the throttle body, and remove and clean the idle air control valve.........put it back on, if the idle is better great, if not it may need to be replaced. also a faulty throttle position sensor could be causing the problem too

dont rely on autozone to check your codes, you can get an inexpensive code reader at just about any auto parts store, and walmart
there are 2 plugs on the eec4 setup a large kinda triangular one, and a single wire plug..........you cannot scan without using both plugs.
good luck!
scott

[Mercracer]

dont rely on autozone to check your codes, you can get an inexpensive code reader at just about any auto parts store, and walmart
there are 2 plugs on the eec4 setup a large kinda triangular one, and a single wire plug..........you cannot scan without using both plugs.
good luck

That is why I told him to ask for someone else......if he got the typical librarian, they were not enough to hook up the single power wire. They have the right tester at AZ, it is just a matter of finding someone bright enough to use it.

[Jason91GM]

hey you guys rock, the moron DIDNT hook up a single wire... just the triangle one. thanks. i think i may pull those parts off my 1989 GM with 89k miles and see if they clean up the idle on my 91. maybe ill go tinker with that RIGHT now cause im SOOOO fuckin bored! thanks again.