OK, for over a week my check Engine light kept coming on. I would open the gas tank door and then close it, start the car and it would go off. But the next time I would start the car, it was on again. Would do the same thing again.

Yesterday my hubby took the cap off, wiped the inside of the cap off, and then sprayed the the whole inside of the cap with WD 40. Wiped off the excess, and NO more check Engine Light! It must get a build up of gunk on the O ring, which caused it not to seal properly.