2001 E39 530i - lean on cold start codes
My 2001 E39 530i has the following symptoms since purchase in 08/2010 @ 137K miles.
When leaving the car parked for 2-3 days without using it runs very rough with a miss on start until the engine warms. Now in 09/2012 at 200K miles after maintenance this is getting worse. 9 engine codes being thrown: P1348 misfire during start c4; P0171 Lean Bank 1; P0174 Lean Bank 2; P0313 Msfire detected with low fuel; P1350 misfire detected during start c5; P1346 misfire during start c3; P1351; P1349; P0300 .....
This has resulted now in the rough running even when the engine is hot at times at low engine RPM's. shutting down the engine for 5-10 minutes seems to resolve except for the constant low level misfire at idle.
When the engine is at highway speeds it runs great with no misfiring unless the cold start very rough condition occurs after the 2-3 days of no use when the engine is cold.
I have looked for arcing at coil packs and see no issue. Misfire is random in all cylinders. Could be a sensor is intermittent? Vacuum leak only on cold start?
Other ideas to troubleshoot?