Many of the Ford and Chev engines calling for regular gas have check engine lites lite up after 5 or 6 years. Many a caused by the cheap gas that is burned constantly in our vehicle. Had it on mine, RV, Cars and Trucks. put 4 cans of Chevran Injector car and cleaner and and filled up the RV with Super premium and put it on the road and ran the heck out of it. After about 200 miles lite won'[t come on again and ran better than ever. Now about every 8th tank full I run a tank of premium. No more problems. Do the same on our cars and pickups, only on a lesser scale, usuall only 2 cars, sometimes 1 will do. Can't tell you this is your problems , but the chances are pretty good. I think the Chevron prduct we use is about 7 to 5 bucks at Wally World and treats 15 or so gals. JMHO. Works for me and our one Licolln has over 300K on it and just used it last month again with excellent results.