Q: I have a Chevy and it has 154,550 miles. We bought a keyed gas cap because we thought that we could protect our car from having the gas stolen. All of a sudden, the engine light went on. I went to an Auto Zone store and they did a Fix Finder report. It showed we had an EVAP, Emission Control System Leak detected. I figured it was the new gas cap, which was not easy to put on. Decided to put the old one back, thinking maybe the threads were compromised. Turned the engine light off, per instructions. Went back to Auto Zone and still getting the same diagnosis. They told me to inspect the fuel cap gasket. How worried should I be?
C.O., Skokie, Illinois
A: The error code that the Auto Zone folks got is most often a bad fuel cap or its gasket. Your first concern is that your car will not pass its next emissions inspection. Although the car will run fine, it is polluting the air. But the cap is not the only source of problems. There is a charcoal canister designed to temporarily hold vapors and then there are various vapor lines, solenoids and other stuff. Since a new fuel cap didn’t solve the problem, you will need a professional technician to examine the system with a computerized scan tool to isolate the culprit.
