P300 , P301,p302, P303 Help
 

2000 ML 320 , after the check engin light came on i went to Autozone and had the guy hook an OBD which indicated mulit missfire codes on bank A,i took the car to the dealer they kept the car for 3 days and said they don't
know what causing the missfire code. any advice would be apprciated.

Ignition system problem..air mass leaning out the mixture....or perhaps a cayalyst failure blocking the exhaust.

thanks Doc. for the reply, but is it that hard for the dealer to not isolate the
specific componant that is failing. they said that they checked the spark plugs
and the coils .

NO, I would have the exhaust back-pressure checked...has your ML had a catalytic converter recall?

i have owned the car for 9 months , but according to the dealer the recall
was done on this car about 2 years ago.

Take it out and drive it like a rental. If it's got a clogged, or partially clogged catalyst, you"ll start losing cylinders at high RPM/load.