[El Gringo]

I have a 2013 E92 N55 I replaced all the coils and spark plugs and I'm still getting this P0300 code The car is idling very rough and when I try to give it gas it gets worse and it backfires can somebody help me out here.

[1Bad335turbopsi]

Have you checked fuel pressure?

[El Gringo]

Fuel pressure is good

[Kevinmendezz]

This code is usually accompanied with other one witch is most likely the cause for this one

[efrain61601]

could it be the gaps in the spark plugs ?
or ur 02 sensors or ur fuel injectors, also check ur vanos solenoids and make sure ur cramshaft position sensors and wires are good and intact and make sure u have no vacuum leaks. those are the only causes i can think of. hopefully this helps

[Corrado68]

Originally Posted by efrain61601

could it be the gaps in the spark plugs ?
or ur 02 sensors or ur fuel injectors, also check ur vanos solenoids and make sure ur cramshaft position sensors and wires are good and intact and make sure u have no vacuum leaks. those are the only causes i can think of. hopefully this helps

Excuse the newbie question, but shouldn't he be able to see most of what you mentioned through additional fault codes? (depending on the OBD2 reader, of course, not all of them detect vacuum leaks).

Assuming that he had no other codes, could it also be some water in the gas tank and, if so, what diagnostic steps could help to determine if that's the case?

PS:
I'd be curious to see how the OP resolved his problem

[mikejones9547]

Looking for some insight as to where to start I have some codes throwing on my 08 335i-
- P2196 stands for “O2 Sensor Signal Biased/Stuck Rich (Bank 1, Sensor 1
- p2096 Post Catalyst Fuel Trim System Too Lean (Bank 1
- p1447 Diagnostic Module Tank Leakage (DM-TL) Pump Too High During Switching
- p0303 DTC is set when the ECU detects multiple misfires from cylinder 3. Could this all be a result of a bad 02 sensor? That’s my assumption but don’t want to just throw money at a problem blindly service engine light is on steadily and randomly get a engine malfunction reduced power light but resets after car is stopped and restarted