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 ...

Q. The “gas cap” light came on in the dashboard of my 2009 Mercury Milan. My local mechanic replaced the gas cap — it was very loose — and said the light would disappear after the car was driven for a ...