2002 Cadillac STS smells of gas fumes

I need you to identify where the smell is coming from, under the hood or the rear of the vehicle near the fuel tank. Also, let me know if the check engine light has come on. It may indicate an EVAP problem.

The mechanic I used did the smoke test and determined the problem was in my gas cap. The gas cap sensor came on periodically. Changing the gas cap has not helped and I tighten it several clicks. The check engine light has been on. Would an EVAP problem be worse with a full tank . It seems odd to me I only have the problem after filling up. In another inquiry you mentioned injector O rings and filler tube leak. Would these be related to the filling up the tank. Thanks

John

go to the dealer and get the updated cap.this is killing cadillac reps. ck. to see if there are any callbacks. gl

Smell is coming from back near gas cap and then into car. No smell under the hood

Have the gas cap checked. Also, I need you to check fuel pump pressure for fuel pressure drop off. Directions are on our homepage under the DIY section. When you turn the key on, the fuel pressure will build at the fuel rail. When you shut the key, it should hold pressure for a while. If it drops of to 0psi quickly, my guess is there is fuel line leaking near the tank. If it doesn't, then I think you have a HVAP leak (FUMES)leaking near the filler tube, vent... At that point, you will need to have the system smoke checked. I will explaine that when you get back to me with your results.