I was having problems with my check engine light coming on for short periods of time. It dawned on me that my gas cap never clicked when I put it on. I went to a dealership and bought a new asap when I realized this. I just wanted to make sure there was nothing else I needed to do. It is a 2002 civic. I feel so dumb....

Cap was bad, but still covering the hole?
Replaced cap, check engine light stays out now? No problem.


If the cap had been missing completely for 6 months, that might have been a big problem.