Loss of power

[LuisM]

I was accelerating onto a freeway this morning, at about 7000rpm in 2nd, when the car suddenly bucked just as I was beginning to disengage the clutch. Shifted to 3rd and reengaged clutch without a problem, but could not throttle past 3900 or so RPM. Engine was running smoothly. Same in 4th gear. Took the next off ramp about a 1/2 mile later, and found same issues in 1st and 2nd. I don't think it was related to the clutch, just coincidental. I suspect that if I hadn't been in the process of depressing the clutch on the ramp, it would have lurched much more as the engine slowed to 3900. It seemed like a fuel delivery problem. The engine ran smoothly without a miss and idled fine. I've had an ignition coil fail before while driving with a more significant loss of power, but the engine ran very rough then. I drove about another mile on the side roads, then decided to try shutting the engine down and waiting a minute or two (in case of an ECU hiccup) (This seems to work with my Windows computer, anyway... After that, all was well, and I motored successfully 20 miles to work. Although I didn't accelerate as aggressively, I was able to reach the higher revs without any problem or hesitation. Any ideas?

Luis
2002 M Roadster

[panasonic]

Why are you revving to 7k to get on the highway?
Your car has to be chipped because I'm pretty sure an S52's normal rev limit is 6500.

[Matt Day]

OP has an S54.

[LuisM]

Here is some follow-up on this problem. It was a bad Mass Air Flow meter, causing a lean condition near red-line and triggering the ECU's "limp home" mode. New MAF, no more problem.

Here is a similar thread http://www.tyresmoke.net/forum/bmw-m...-7-000rpm.html