My car's gas tank was replaced recently and 3 days later the 'Check Engine' light came on and stayed on. Plus, a gas cap sign is now showing. I tightened it and it seems secure. What does this mean?
I would take it back to the dealer that put the tank in and have them check their installation of the fuel tank. The lights should be off and no leaks detected with the new fuel tank. You may have a major vapor line leak and gas vapors are more flammable than liquid gas.