A150 Recurring P0304 code

Question

P0304 keeps coming up.
Coils & plugs changed - still comes on once a week.
No loss of power - no running problems.
Cannot stop code from repeatedly coming on.
Local garage has checked several times - no fault apparent - code reset. Car runs Ok.

Why does this keep happening ??.

Answer 1

Hi there,

Have your shop do a leak down test. Sometimes you can have some carbon buildup on one of the valves and it will cause the misfire code. A leak down test should determine if it's the problem or not. This test is better then a compression test cause it will show smaller problems.