On a trip to Florida week of 22 Nov 10, after fillup the message "tighten Gas Cap" kept coming up. I tightened it and then it went away until the next fillup. This week, I have the Check Engin Light on and then sometimes it will come up with the "Tighten Gas Cap", but the check engine light still stays on. I am on the 3rd gas cap. Two from Buick and 1 from Avanced Auto. Now I am told that I need to run the car 7 times to get rid of the check engine light.
Check gas cap came on occasionally. Replaced gas cap and problem returned. I replaced the purge control valve (ac-delco part 214-1473,reset the computer and the problem has been fixed. The purge valve was not sealing when "closed" which would be similar to a bad gas cap.