I thought it would be a good idea to upload some print screens from two logging events. One with OK revs, one with bad. (Done while revving with a stationary car.)
So here goes:
First, the good one:
The the bad one:
I can't make sense of it. It looks very similar, only the bad one shows the slight hesitation in the RPM, and that the AFR goes really lean...
Hope someone else can figure it out?