My base R56 has been misfiring under load, with intermittent uneven idle, occasional stalling and occasional rise in idle.

Here are the recent codes while experiencing these problems (all are pending faults except P2187):

P2187 Powertrain too lean (current fault)
PO300 Random Misfire (2 times)
PO302 Cylinder 2 Misfire (3 times)
PO303 Cylinder 3 Misfire (2 times)
PO420 Powertrain catalyst system efficiency below threshold
PO507 Powertrain Idle control system RPM higher than expected
P2178 Powertrain System too rich Off idle
P2187 Powertrain System too lean at idle

I would love the problem to be a coil pack and will check through substitution and/or testing, but I would think that would throw a coil pack code.
I'll do a compression test as well.

Update - opened hood to find dipstick partly out of holder and oil spewed around. Down 2.5 QTs. What caused the dipstick to partially eject? This happened once before a long time ago.

Another update - plugs were dirty, cyl 4 plug was a mess. All had too wide a gap. Cleaned and gapped to .032.
Had a new vanos solenoid in stock, so replaced the one on the intake side
Did brief test run. No hesitation, No codes. YET - But idle wanders a bit.

Any help?
Thanks!

 

I’d be tempted to replace coils and plugs, and possibly O2 sensor, then see what happens

 

The O-ring on the dipstick is worn out and there’s too much oil pressure due to overfilling. Are you using synthetic 5-30? It’s good that you replaced the vanos solenoid ‘cuz they tend to get filled up with gunk.

 

Too much pressure in the crankcase usually means a faulty or plugged PCV system. PCV = Positive Crankcase Ventilation system. If you can properly relieve the crankcase pressure, it will find a way out. In this case, through the dipstick tube.

 

Thanks! I did replace the PCV years back, possibly after the last dipstick issue.

 

Nik had the answer.

I replaced my PCV and all now seems well!

The faulty PCV seems to have lead to oil in the cylinders, which fouled the plugs and may have been the culprit in blowing oil out the dipstick tube.