My 2003 MC
also came down with this. Random problems, ie stalling at times, repeated need to start the car before it would hold an idle, rough idling needing to gas the pedal while at a stop light, cutout of full power (car would idle, but would have no "ooomph").
Lights on the dash (both "Service Engine Soon" and the EML) coming on, going out, staying on until multiple restarts.
Car at the time had approx 8600 miles logged.
A call to my dealer (MINI of Peabody (these guys are the best, by the way...)), they had me in in a very short time. The replaced the wiring harness in the engine compartment and the throttle body. Problem looks like it was from the electrical connection to the throttle body. Did a bunch of other stuff too, they really took care of me and the MINI.
I've talked with others that have had the same problem and the same fix. I've put another 1500 miles on the car since the repair, all is well.