My 85 vette is having some problems with rough idle. It starts fine, idles smooth until warm and then while in gear starts idling rough. I have to put it into neutral at stop lights because it sounds and feels like it's going to kill on me. The volts also go from 13.5 to 11.0 during this rough idle time. I did replace the battery but it still seems like the volts are too low. The exhaust also smells really rich to the point the smell sticks to my clothes and smells up the garage. I think I have two separate issues but am at a loss on what to do.

Ps I'm new and this is my first posting!:beerbang:

Sounds like an alternator problem.

My 85 vette is having some problems with rough idle. It starts fine, idles smooth until warm and then while in gear starts idling rough. I have to put it into neutral at stop lights because it sounds and feels like it's going to kill on me. The volts also go from 13.5 to 11.0 during this rough idle time. I did replace the battery but it still seems like the volts are too low. The exhaust also smells really rich to the point the smell sticks to my clothes and smells up the garage. I think I have two separate issues but am at a loss on what to do.

Ps I'm new and this is my first posting!:beerbang:

Take it to about any auto parts store and have them do two things:
1. Alternator check
2. Check for any fault codes.
Let us know what they tell you.

Sounds like an alternator problem.

:iagree:
ECM control is dependent apon voltage.
Too low and it won't operate properly.Volts should be 12.8 or better

It sounds like to me your oxygen sensor has gone bad and is allowing your idle speed to drop so low your alternator isn't charging.

If you haven't changed your oxygen sensor lately, it is probably time to. Every 30,000 miles is what is recommended for changing them.

And a bad oxygen sensor will cause the exhaust to stink something terrible; like you're complaining of.

It sounds like to me your oxygen sensor has gone bad and is allowing your idle speed to drop so low your alternator isn't charging.

Bad O2 won't affect idle.If sensor not operating engine will stay in open loop fueling just the same as it does for the first 5 min from startup.Open loop fueling is from a fixed programme ; no adjustments unlike when running in closed loop where the ECM takes the O2 readings and adjust fuel.

Bad O2 won't affect idle.If sensor not operating engine will stay in open loop fueling just the same as it does for the first 5 min from startup.Open loop fueling is from a fixed programme ; no adjustments unlike when running in closed loop where the ECM takes the O2 readings and adjust fuel.

I've owned my '82 for 22 years, and every time my oxygen sensor has gone bad, my engine runs like crap and slows down so slow, my alternator quits charging. And it acts like it's running real rich. So I assumed that is what is happening in this case.

I think I have two separate issues but am at a loss on what to do.

Ps I'm new and this is my first posting!:beerbang:
I agree with the two separate issues comment. Since the alternator will put out 13.5 volts, I doubt there is anything wrong with it. It sounds to me that the low volts are due to an abnormally low idle. Do you have a "Check Engine" light on? Have you checked for any codes set? There are many possible causes of your poor running. A code or two could get you started in the right direction. Lacking codes, I would start with the MAF system on an '85, more specifically the MAF burn off module. Whatever you do, don't waste money throwing parts at it. Spend your time diagnosing and trouble shooting, not replacing good parts.

RACE ON!!!

Thanks for all the replies. I plan on trouble shooting through each of your suggestions. I will let everyone know what happens.:beer-fresh:

Bulvine