2001 540i obd2 codes 1341,1343,1345,1347

[golfgod]

misfire bank 1-4...i changed plugs, both cam sensors, all 8 coil packs are good and the fuel filter is new as well. i dont know what test i could do for the maf sensor but it is not clogged nor dirty. the best clue for all the smart ones out there is that i could drive it but wont carry past 4000 rpms then the check engine light starts to flash. this car was running sweet until just today, it started acting up which is when i googled the codes and the forums had one man with the exact same problem. i changed everything i could think of and did not see any vacuum leaks. i have not done a compression check yet because i have to get that from my buddy. no oil in the radiator and no water in the oil so i dont think i have a head gasket blown, but not sure...
any thoughts? thank you in advance for helping out a newbie to this forum, but love every BMW i have ever owed and worked on

[westin]

well the light will flash,beacause you running the risk of burning your cat bank converters,mifire on one bank is strange for all four, but check your plug boots for oil or if they getting ecu signal , im not sure how you cofirmed the coils are good but scoping is best, also if you had a vacum leak it be idling prety bad, same if the maf was bad how MAF sensors on this car?

[golfgod]

well when i changed everything there was no oil all around the boots...i would have explained that symptom....the coils measured .8 ohms between primary and secondary and all measured the same so i swapped sides to see if it would change codes, but still the same...i also noted no vacuum leaks but i cannot be for sure...all of this happened after starting it up after running sweet the whole time....it almost seems maf cannot be tested with a meter? i need software lol

[westin]

You van disconect the maf if it runs better,find your problem crude but it seems to work. On other thing its kinda of a long shot cloged cat . Sorry cant more help ,but its weird for one bank all 4 cyl misfiring

[golfgod]

Thanks that's a good point I'll check the cat and unplug the MAF and let you know... I'm stumped