Mine does the same thing, 3ri tune full exh and KWI clutching, I think it's in the clutch, trying to shift up or down at that speed, go a little faster and it shifts.. slow down and it doesn't do it.
Is it only in sport mode? I’m thinking it might be when the throttle is more sensitive in sport mode. Like is it better in eco mode?
I’m wondering if your foot is bouncing on the gas pedal in the more sensitive sport mode….
Check for bent axle or driveshaft, takes very little of a bend to be able to feel it. Next i would inspect clutches very well.Having similar issues and belt change only helps a little. Does it on both stock and Dynajet mild tune. It did not do this a few hundred miles ago.
If it's always, it's just reading the wrong value then, 14.7 is stoich and around what idle AFR is. You'll drop into the 10/11s under high load. The X3 runs way rich, but it helps w piston cooling and fuel economy isn't really a thing most care about in this application.My Dynojet always tells me the requested AFR is 14.7. I am using their canned tune currently. I would have to load the stock tune to make any programming tune changes.