Hey guys! So this car has been irritating me to no end, it's an 08 535i with 74k miles, and it has been misfiring since I got it. At first I would get lean codes, then rich codes, but now all I get is misfire on Cylinder 4. I threw in new spark plugs, tested all my coils, and replaced the injectors. I also have a new O2 Fuel sensor, and already checked for any leaks. I'm pretty much running out of ideas here, could carbon build up be causing this? Cylinder 4 pretty much misfires constantly.

I would appreciate any insight!

 

You should post check out n54tech.com to find your answer or at least post this question there as the people on that site are a lot more active than on this site and are extremely knowledgeable.

 

Alright, I'll try that!