DeLorean247

Well my car still has a fluctuating idle and feels kinda rough while reving up high in park. Sometimes it revs up very smooth though but rarely. Everything feels great when I start it cold and it runs like I would think it should run like untill about a minute in then the idle wants to drop off and it surges at stop lights by about 100 Rpm. I have checked my MCS and after being confused why it was not clicking with the key on and engine off (some od 82 thing) it does click when running. I am starting to wonder if it is the O2 Sensor I have never changed it and I doubt the old owner did either. But I dont get a check engine light or a code and even unpluging it after its at operating temp dose not give me a light. Why is this?

Thanks for any help, you guys are the best!

five7kid

iTrader: (14)

Is the bulb burned out?

DeLorean247

Nope it comes on before I start the car and I can get code 12 out of it sorry I did not put that in the first post.

five7kid

iTrader: (14)

It's possible for the O2 sensor to be weak and not set a trouble code. Since they aren't that expensive or hard to replace, might as well change it and see what happens.

Otherwise, checking IAB dwell is about the only other thing that comes to mind.

DeLorean247

I guess ill try a new one but isent it weird it wont give me a check engine light with the sensor unpluged? Also whats IAB?

Thanks

DeLorean247

OK went and did some tests on my egr system just to make sure it was not the problem. I get 30ohms resistance on the solenoid so it is fine i guess but only .3V on the connector. no matter where I put the throttle. I also dont get a trouble code with the EGR solenoid, O2 sensor, or TPS unpluged But do get one with the MCS unplugged. Is the computer in this thing broken or just not to smart for 1982? on ther cars iv seen you can hear the egr solenoid clicking at idle isent mine suposed to do this?

Thanks Again.

five7kid

iTrader: (14)

I've never tried disconnecting the O2 and watching for a trouble code.

It's the MCS solenoid that should click when you first turn on the ignition. How long it clicks w/o starting the engine varies from vehicle to vehicle.

IAB = Idle Air Bleed. Better to get a book (Haynes shop manual or Doug Roe, "Rochester Carburetors" in the title of each) and read about it than try to describe it.