Once the light came on, and after you took gas cap off and back on, did you ever reset it by unplugging the battery? My 3g eclipse had the code because the cap wasn't on tight one time. Was told I had to reset it after I put it on there or the light would stay on. The driving was not effected or anything, once I unhooked the battery and hooked it back up a few minutes later the code never came back on.