2001 mercedes c240.

i have a misfire in cyl #4.changed coil,wires,plugs and swtiched injector.the car runs and idles fine.the misfire only occours when you punch the gas.stays missing until the code has been cleared.checked harness no sign of corrosin or wear.any ideas?

reset ring gear adaptations with your factory compatable scan tool. if that does not fix it check for broken exhaust valve spring.