The gas cap is one part of your vehicle that we bet you don’t give much thought to in spite of how often you use it. The thing is, a gas cap does a lot more than simply close off your vehicle’s filler ...

Dear Doctor: I have a 2002 Audi A6 2.7T. When the “check engine” light came on I called the dealer and they asked if I had just filled the tank and I told them yes. They told me to tighten the cap and ...