BMW 318i n43 engine misfire on cylinder 3. I Replaced all the usual stuff, coils, spark plugs and fuel injector, however none of it worked. The engine is chuffing heavily and if u look closely u can see the fuel injector seems to have Exaust fumes coming out of it (at least that’s what it smells like). The old spark plugs seems to be very sooty and 2 of them in 3 and 4 were oily. I’m not sure what the issue is but it is constantly misfiring and everything I’ve tried seems not to work if u have any advice please let me know.