On two occasions I went to Jiffy Lube for an oil change. Both times, the "check engine" light came on two days later. I figured out the first time that it came on because the air filter housing had not been closed. The second time, I told the service person that I did not want him to check my air filter because of the inconvenience the last time. Not surprising, he did it anyway. I took it back to the shop and told them to figure it out. They could not. I went home, popped the hood, opened the air filter housing and discovered that a hose had not been re-connected. That was the problem. I emailed Jiffy Lube's home office with a detailed account of my experience and never received the courtesy of a reply or acknowledgement. I was informed by a co-worker that in 2008, Jiffy Lube had to pay $5M to settle a fraud case (unfair business practices). Two of the most significant violations were that they were charging for services that were not performed and recommending unnecessary services. I will NEVER go back to Jiffy Lube.