Gas Fumes - How to proceed.

My daughter's 95 Camaro, 3.4 has a rough idle and we can smell gas fumes. I can not detect a gas leak. Thus far I have replaced plugs and wires and the car ran fine for a few days. I have done some experimentation and have found that all the plugs are recieving spark. I noticed while examining the plugs that they seem to have a lot of soot on them which seems to indicate too rich a fuel mixture. Still, all plugs are firing. I searched this forum using "Gas" and "Smell" as search terms. Came up with the following possible problems:

O2 Sensor
Stopped up catalytic converter (no rotten egg smell though)
PCV Valve
Knock Sensor
Fuel injector pressure regulator
EECS Filter.

I'd like to know if you guys have any other ideas and how would you proceed to narrow the problem down and fix it. My daughter is lost without her car but doesn't have a lot of money so dear old dad is trying to help her out.

Thanks

Have you tried running the car for codes? Your answer might be there..

The rough idle sounds like your ignition control module, but again.. check for codes first.

[QUOTE=Rally Sport]Have you tried running the car for codes? Your answer might be there..QUOTE]

Haven't checked for codes. Don't see the engine light on though. It seems that I have heard of soft codes or as I understand it, codes that don't trip the check engine light. Is that right?

Yes thats true. Sometimes codes wont trip the check engine light.

Check around the injectors for gas dripping at the rail while the car is idling. Alot of times over time the o rings that are used start to dry out and don't create a tight seal anymore and fuel spills out and collects on the lower intake manifold. Then those vapors make there way into the car. Its fairly commen.

i have a smililar issue....ppl can smell my exhaust, under parking lot driving conditions, in a vehicle behind me....when i get on it, i leave a slight dark exhaust trail...i think i might be running too rich, there are no leaks or bad looking wires oo sensors....no code either.....it's leaving a charcoal looking film on my back bumper, just over the pipes....someone suggested maybe, my inconsistant fuel sources and grade might be blowing out my cat (hense the charcoal type exhaust)? anyone got any ideas for me?

THanks,
Tim

i have a smililar issue....ppl can smell my exhaust, under parking lot driving conditions, in a vehicle behind me....when i get on it, i leave a slight dark exhaust trail...i think i might be running too rich, there are no leaks or bad looking wires oo sensors....no code either.....it's leaving a charcoal looking film on my back bumper, just over the pipes....someone suggested maybe, my inconsistant fuel sources and grade might be blowing out my cat (hense the charcoal type exhaust)? anyone got any ideas for me?

THanks,
Tim
You do know under heavy throttle your on Fuel injected systems the ECM/PCM turns off the 02's and uses a preprogrammed map to tell it how much fuel to dump and what timing to use. So if you added any modifactions that would be adding extra fuel it would not use the o2's as a reference. If it is also doing this under less than 1/2 throttle responses I would say either you have alot of carbon deposits in the your intake manifod or around your tb or even in your combustion chamber or your O2's are no longer good. There could be other causes as well though.