Gas Cap check. I'll go to Reeves Tuesday, hopefully. If had been a gas cap, i would have had to say it was something else. My credibility would have been shot. I troubleshoot Aircraft Avionics, Data Bus lines, and Autopilot all day, and i could find out my gas cap wasn't on. That would have sucked Really though, the gas cap was tight, i even re-tightened it. I honestly never heard of a gas cap loose causing a CEL. Maybee it's a bad gas cap sensor though?