NathanJT
I'm pretty sure, I experience what you are describing.
It occurs only on light throttle (eg. constant speed) and usually just under 2000rpm. (Following other traffic?)
If the throttle is pushed on just slightly, you feel a hesitation for part of a second, then it feels normal.
I've put it down to another type of 'turbo lag'....
Not because it's just coming into the turbo range. (On my 325, this starts about 1200rpm), It's beacuse the engine is so lightly loaded under these conditions, that there is not sufficient exhaust flow to keep the turbo spinning at operating speed.
It's not just engine rpm that spins the turbo, it's the exhaust gas flow.
If you are never particularly gentle with the throttle, you'll never experience it...
I'm not going to let a dealer fook about with it 'cos I'm sure it'll come back with more problems than it went in with!!!
Leave well alone mate!
