I have an '01 929 that starts and idles fine and runs great on top but is dropping a couple cylinders in the mid range. Once I hit a high enough rpm all cylinders come back on and it then runs great again. I have checked the fuel pressure regulator but there is no fuel leaking out the vacuum line, is it possible its bad even though it is not leaking?

 

Doesn't sound like a fpr issue to me. Do you know which cylinders a cutting out, or if they really are? What rpm does it start and clear up?

 

I do not know which cylinders or exact rpm as I don't have a gauge but its from about 1/4 throttle to 3/4 throttle. It just falls flat and definitely is not running on all cylinders but once you get past 3/4 throttle it picks back up and will sing to the rev limiter. What else could it be other than FPR? I have checked plugs, coils, injectors, throttle bodies, throttle position sensor, HTEV exhaust valve, stator, reg/rec.