[NezPez]

I have a 2007 328i N52 with 88k miles and as you can see in the title I have a misfire, but recently I have been getting frustrated with diagnosing this issue.

I first got the misfire code only when I would go full throttle on the gas, but it would go away along with the check engine light when I would cycle the engine, so I tried to just baby the car. Then, after a month or two it developed into a random misfire every once in a while idling. After, the car would have the misfire while getting up to speed, but it was random when it would happen. Finally, the misfire got bad to the point where my check engine light comes on while idling, but again not on every start and its random how severe it is.

I changed spark plugs, swapped around the fuel injectors to see if the misfire followed(did not), and did the ignition coils, swapped them around also, and cleared codes.

My question is WHY!? Valve cover gasket, Eccentric Shaft Sensor, DISA Flaps?

[IchMagBMW]

You might have vacuum leak near cylinder 6. The usual suspects are PCV diaphragm, PCV plastic vent hose behind the valve cover, oil cap. Sometimes brake booster hose leak would trip misfire code too.

If no leaks are found, then you might want to check the engine compression on that cylinder.

If compression is good, then you might have engine timing being off. Stretch timing chain would cause misfire codes too. It would start with one cylinder being misfired then progress to multiple cylinders being misfired. Hope this is that the case for you.

Seth,