'15 E84 N20 - P0300, P0301, P0302, P0303, P0304 all at once... then fine

[5mall5nail5]

Hey all -

Wife went to grab groceries in the E84 last night. We had started the car about 3 hours prior and moved it over in the driveway so I could take another car out. Then she started the E84 and got "Engine Malfunction" and rough running. She shut the car off and started it again - check engine light on but the engine ran fine. She came back inside. I went out, checked under the hood and engine cover for squirrel or other damage (lot of that happening around here) - all good. I start the car, CEL still on, but I rev the engine off idle listening for chain noise or something and its smooth as butter - turbo spool, blow off. Everything sounds find. I grab my OBD2 adapter and check in torque and have:

P0300, P0301, P0302, P0303, P0304 - misfire general, and then each cylinder.

Weird. I did not experience it stumble/run rough - I cleared the code and drove it for 30 mins without issue. Kept Torque app open - it made 16.5 - 17 psi of boost, AFR was down to 12:1 on load and 14.6-15 on cruise. Everything behaving.

Could have been a fluke? I replaced the plugs about 5k miles ago with OE. Car has 65k on it. No obvious issues otherwise.

Thanks!

[Westies]

I have a '13 N55, but I have the same thing happen about 1-2 times per year- engine malfunction warning with various misfire codes. Every time I just turn off the car, clear the codes and restart, and everything is fine.

Mentioned this to the dealership once a few years ago, they looked everything over and couldn't find an issue or reproduce it and said all checked out.

[5mall5nail5]

Originally Posted by Westies

I have a '13 N55, but I have the same thing happen about 1-2 times per year- engine malfunction warning with various misfire codes. Every time I just turn off the car, clear the codes and restart, and everything is fine.

Mentioned this to the dealership once a few years ago, they looked everything over and couldn't find an issue or reproduce it and said all checked out.

Thanks for the reply - I actually have a good amount of experience with engine control management and the only thing I can think of here is that there is an acute issue with either the crank position or cam/eccentric shaft position sensor. Like the engine starts "out of time" electronically (not mechanically, obviously, but with N20 chain issues that was my first panic though when my wife told me the issue) as if the cam position sensor signal was on the edge of "out of phase" and the engine injected/sparked out of time... but who knows.

Thanks for confirming another instance of this. Like I said, and you confirmed, the car started 100% after this instance, cleared the codes, did like 10 - 15 miles of spirited driving without a hiccup. Here's hoping it's nothing. I also wanted to avoid a dealer good chase.

Thanks again