Another interesting point is that the TPS sensor doesn't seem to be acting as I would expect it to.

TPS is at 0.0% when at idle. When not moving (in neutral), I would expect the TPS % to smoothly follow the accelerator pedal as I step on it. Instead, a change doesn't register until I push the pedal halfway down and the RPM's are pretty high. If I peg the pedal, I can briefly see the TPS % in the 90's, but it is not steady.

I took the car out for a test drive and watched the TPS%. It does change and I can see it occasionally in double digits, but I couldn't see any pattern.

This may be just how the TPS operates on the E53 but I thought it was worthwhile to note.

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cmelkoni
2003 X5 3.0i, manual