About Tom Joy Expertise Have expertise from 1960 thru 1999 CADILLAC'S in carb, fuel injection, brakes, suspension, CHECK ENGINE lights, ignition, transmission, A/C and heating, Electrical problems and all electronic components. if maxed out you can contact me at: tomcjoy@msn.com.
Expert: Tom Joy Date: 8/29/2007 Subject: O2 Sensor
Question I have a 1990 Deville. I've checked the codes (had bad mpg and the car is running really rich of fuel) and found out that i needed a oxygen sensor among other things. The first week of Aug 07 I put a new oxygen sensor on the car, and it corrected the problem. I have noticed three weeks later the problem is back. If I idle my car for 3-4 minutes i can see gas on the ground where the tailpipe is. Is there more that I am missing? I think it is a computer problem at times because I can reset the computer and it will run like a dream, but 20-30 minutes later the computer catches up to me again. I got a tune up earlier this year, with new wires, plugs. I have put a new converter on, changed the oil every 2500 miles, transmission every 15k and changed the radiator fluid in 2/07. The car has 176k on it.
Answer Are you POSITIVE that it is gas that is coming out of the tail pipe or just water from condensation. This IS very unusual as you would get a CHECK ENGINE light from the oxygen sensor indicating that the exhaust was running RICH.
If you put some of this tail pipe fluid on your finger does it smell just like gas ?.
The ONLY thing that would cause this would be:
Leaking fuel injectors which you could see dripping gas after the engine was stopped and the air cleaner was removed and you physically looked at the 2 fuel injectors to see if they are dripping gas into the engine.
A faulty ECM (computer) which is delivering to much gas to the engine due to an internal fault but again the CHECK ENGINE light would come ON and a RICH exhaust system would be indicated.
