2001 X5 Runs Rough After Warm, Occasionally Stalls
 

2001 X5 4.4 with 130k

Car starts up fine and runs ok when its cold, after its warmed up it occasionaly will run a little rough driving on the highway. It seems to come and go, when running rough at highway speeds I feel some vibration in the steering wheel and fuel economy indicator shows I am losing a few miles per gallon.

Things get worse if the car is warm and I am driving stop and go in city traffic. The car feels like I am running out of gas while trying to accelerate and will occasionally stall when decellerating and I am "almost" at a stop. Downshifting also feels very rough.

Check engine light has been coming on and off, brought it in to the shop and they retrieved codes for running lean on banks 1 and 2. They cleaned the MAF, did a fuel system clean and flush and replaced some bad vacuum and oil separator hoses.

I was OK for a few days but I am now back to square one. I don't want to keep bringing it in a replacing parts at random.

I am thinking about replacing O2 sensors, crank and camshaft position sensors. Any feedback would be great.

Were you able to record the exact codes? If so, what were they?

I too am leaning towards sensors as heat soak is a primary reason they can start acting strange when the engine warms up.

Im having the same issue. What octane rating should these cars be running minimum? My wife filled it up on 91 Octane and not sure if that was the problem. Also if anyone can help with other issues i have below.

1. Radio does not stay on channel and keeps changing like its on random
2. Park brake does not seem to work.

Well, I can't relate hard downshift(tranny), Steering wheel play(wheels), and running rough... seems interasting though

Could very likely be the Mass Air Flow Sensor, or Oxygen Sensors. When it gets worse, it will set a code. You can try cleaning the Mass Air Flow sensor wire in the intake as if they get oily, it does not function properly, and such symptoms will be evident.