My 1999 Silverado has a #7 cylinder misfire according to Autozone test.
I replaced fuel injector for this cylinder,no help. The vehicle runs rough when idling, however it has excellent power when driving.The exhaust sucks and blows using dollar bill test. I have also replaced plugs & wires.The "Service Engine Soon" light stays on constantly.This is driving me crazy. Help!

compression test cyl 7 (bad exhaust valve)