The stumbles.

[jimincalif]

This may or not be it, but I had this issue and it was a bad spot on the resitance track in the AFM. I loosened up the set bolt on the sweep arm and pushed it down the shaft ever so slightly and it cleared right up. This sets the sweep arm into contact with a fresh track on the resistance plate.
Ron

Ron, THANKS for this! I read the article and did this last night. Today my persistent mid-range/mid throttle stumble is GONE! I figured it had to do with the FI system somehow but would have never figured this one out on my own.

Jim

[rlux4]

I'm glad I was able to point this article out. It's amazing the difference that it makes if in fact a bad spot or two on the track is the culprit. When I first read this article I thought it through and it made sense that the bad spot would probably be where the sweep arm spends most of it's time, which is in the cruising speed RPM range.
Ron