Wasoup

Hey guys, have a 2008 ML63 amg. Recently its been misfiring on just cylinder 5. Have replaced all the plugs, cylinder 5 coil and injector, but still misfiring.
Once in a while the car runs perfectly with no misfire or other issues.
Also noticed that when a full tank is put in the misfire disappears for a few minutes.
As well when we replaced cylinder 5 injector it ran perfect for about 5 minutes before starting to misfire again.

The codes coming up are P0205, P0305, P0050, P0330.

Anybody have any similar issues?

Solo wing

P0050: HO2S Heater Control Circuit B2S1
P0330: P0330 Knock Sensor 2 Circuit Malfunction (Bank 2)
What is the mileage? at that age, the O2 sensors might need replacing.
Also, consider replacing maintenance items, like intake manifold gasket and PCV.

Good luck.

ItalianJoe1

Intake manifold gasket leaks are common on the higher mileage early 156s. Especially since it's a front cylinder, I'd check that next.

Wasoup

Thanks for the replies. The cars got 185kms. I will definitely check the intake manifold gasket next.

Whats got everyone stumped is how the misfire disappears for a few minutes when the car is filled up.