xDrive50i, P0641, and misfires...
 

Hey everyone. Long time lurker, first time poster. Vehicle in question is a '13 X5 xDrive50i with around 115K miles on the SAV but only about 45K on the motor (it was replaced under warranty).

Recently got a misfire code for cylinder #7. Coil and plug were replaced. Following that there was a rough idle and a few miles down the road it started shuttering again. Ended up with codes for cylinder #5 misfire (P0305), Bank #1 too rich (P0172), and sensor reference voltage A circuit/open (P0641).

Swapped the #5 coil/plug (suspected bad) to cylinder #7 (just replaced/known good), cleared the codes and fired it up. Now I'm sitting with cylinder #5 misfire and cylinder #6 misfire. Didn't let it run very long or it may have gotten the P0641 again, I'm not sure. In any case, the fault did not follow the plug/coil so I am doubting that it is the problem.

Other items that may be of note. The short term fuel trim on Bank 1 is way higher than Bank 2 (20-25% vice -3%) and the Bank 1 cat temps were 200-300F cooler than Bank 2.

Thoughts?

You may have a faulty injector dumpign fuel into one cylinder; whacking out the AFR; washing the cylinder walls; diluting the oil with fuel. Its the fatal flaw of the recent bmw v8s

When was your motor relaced? Why? Any reason to suspect it has the older, flawed injectors?

Motor was replaced two years ago because of a mechanical failure. Think sounds of mechanical carnage. I would be willing to be the original injectors are still installed. They didn’t replace coils so I doubt they replaced injectors

Is the short term fuel trim measuring fuel flow or ECU requested fuel supply?