CEL on, rough runnin after oil change
My 2002 Subaru Sport has been the perfect car. Low mileage, only 29,000 miles. Took it in for an emissions test and oil change. Test passed. On the way home it started idling rough. Over next few days and several short trips totaling 50 miles, sputtering got worse, especially at starting or starting at red light or acceleration. Yesterday it backfired also. Coming home the CEL came on - steady, not blinking. The timing strongly suggests something happened at oil change or emissions test??????