[thedragonseven]

Great post!

I don't have an X5 any longer, as I've moved to an M6 Gran Coupe. This M5/M6 engine is a S63Tu - so very much related to the N63Tu in your X5.

I also have the RaceChip Ultimate on my car and have it set to S1=1, S2=D setting (it was also 1,B stock). Maybe give that extra notch a try.

On the M5/M6, it takes removing one screw for each intake, removing the intakes, and locating the sensors mounted on the intercoolers. After several times now, I can do it pretty much in 15 minutes or less.

But, looking at the X5 engine bay it does seem some things are squeezed where in the M5/M6 they aren't as tight in those areas.

Also one thing to note, I get drivetrain malfunctions from B to E, regardless. I never lose power delivery, never lose driveability, and never lose throttle and engine response. It just comes on and sometimes goes off later.

As some have noted, and I confirmed with the director of my BMW service department, the fuel/air/exhaust sensors are very sensitive.