Hi, I'm fairly new here. I've read a lot of posts about this as its a very common issue with N5x motors. Bit of a weird story here, anyway. My brother bought an e90 330i about a year ago, I tried helping him work on it as I had general knowledge on cars but not specifically bmws. He had a misfire on cylinder 6 code, and some maf sensor codes. Back then, we unplugged the maf sensor and threw in a new air filter and the misfire code never came back after we cleared it. He recently told me that it always had a slight hesitation or slipping feeling.
Anyway fastforward to now, I bought the car from my brother in september and it seemed to drive perfectly fine without the maf sensor. I changed the oil immediately after getting it and it gave me no issues for a while. I installed a silicone boot (intake resonator delete pipe) and it seems to have started to hesitate ever since. I made sure the intake was tightly sealed, and I even bought a maf from someone parting out their n52 330xi which threw the same codes. I noticed upon plugging in the maf I got a new code (P1415) and it gave me the same fault codes (P0103, P111F, P0113) as the old maf, so I'm thinking the wiring for the maf might be bad or its reading low voltage because of the vacuum leaks.
My available options:
- Buy a brand new maf
- Clean the vanos non-return valves
- Replace literally EVERY vacuum line on the car
- Replace the spark plugs even though it says they have 70,000 km left
- Replace the cylinder 6 coil (would rather not put forth the money for all 6)
- Replace the fuel pump
- Clean or replace the injectors
- Sell the car
What I've done so far:
- Oil change
- Purchased but not installed new spark plugs
- Replaced the oil filter housing gasket
- Ordered a new oil cap as it seems to be losing oil from the current one
- Tried both maf sensors I have
- Capped off the broken vacuum line that goes back to the exhaust flap
Anyone have any suggestions? Any help would be much appreicated, sorry for the novel
Edit: The hesitation happens at low RPM, it seems more or less fine when I floor it. Fuel consumption has been pretty high, but seems to have gotten higher since replacing the oil filter housing gasket and capping off the vacuum line. There is no oil in the spark plug wells, and my valve cover gasket itself seems fine. There is no ridiculous vacuum when I take off the oil cap while its running so I think my ccv is fine?