i have an 89' hatch and it smells like gas every now and then, looked under neath the car and couldnt find anything. took it to the shop and they couldnt find anything...also when ever i remove the gas cap to get gas it relieves a lot of pressure, i dont have a cel so it can't be the o2 sensor.

any help would be great, thanks

 

cat?

 

check your evaporative emissions system, make sure its working properly. It will draw off excessive fuel vapors from the fuel tank and feed it into the engine under certain conditions. Tracing the leak may be harder but checking out the evaporative emissions system may help out if its making too much pressure and the fuel cap vents it out, or it leaks from some other place. You'd have to basically check everything, the hoses and fitting under the hood, and at the gas tank, and the fill pipe as well.

btw the cat wont cause poor mileage. It only cleans up whatever comes out of the engine. Your O2 sensor could still be bad. The ECU will only be able to test it's operation under very specific conditions such as extended engine braking, otherwise it assumes it's not hot enough if it's not returning a reading.

Janos