Ok so first things first... I did a search.

My check engine light came on right after I did a fill up, I then tightened the cap and a day or 2 and about 80 miles later it went away. It was off for about 2 days, then all of a sudden it came back on. I have yet to tighten the cap again, but am now wondering if it could be anything else. I assumed that if it was something other than the gas cap then it would have never shut itself off like that. I will have time on wed to take it in, but just kinda want some peace of mind untill then. Is it possible that I just need a new gas cap bc the one I am using now just dosent seal as well as it did in the past? Any thoughts or ideas will help me out alot. Thanks,
-Mike

ps. If I take it to autozone and they check whats throwing the code, is there one that says gas cap or will that read something else?