Rough idle....SES light

[Chris '94 3.4]

It's a '94 Camaro w/ the 3.4 and an automatic. 175K miles. I just bought it about 6 weeks ago. Problem is, it has a rough idle and the SES light comes on. It has never died while idling, it just idles rough. When you give it gas it runs smooth. It smells a little rich at an idle too. I've changed the PCV valve, spark plugs, air filter. The wires are soft and they don't seem to be jumping fire (no sparks at night with the hood up and the engine running). Could it be the O2 sensors causing rough idle?? What else??

Regarding the SES light, it mainly seems to come on when you are driving a constant speed and then let off the gas to coast. I tried to check for codes but the SES light won't flash. In the instruction manual for the code reader it says that if the light doesn't flash at all with the code reader plugged in, then there is another problem somewhere that needs to be fixed before the code reader will work. Any ideas???

Thanks in advance for the help.
Chris

[hockeyman]

The code reader should give you some info.
I'd replace the spark plug wires anyway. Just because you don't see them arking, it doesn't mean they are in excellent shape. There could be a split inside of the wire causing an ark that you cannot see. My car misfired like crazy until I narrowed it down to a faulty wire.
If you are still getting a misfire after replacing the wires, then I'd get the car professionally scanned.

-Marc

[MIKE M]

same thing happened to me and I found myself with an overheated car about a month later on the side of the highway. $1700 later my car is fine but I'm broke. My valves warped and had a blown gasket leaking coolant very very slowly. My advice is to check it out and dont keep driving it till its fixed.