I have a 2003 MCS with a 17% reduction pulley.
It has 160,000 miles.
For the last 10-20K miles I have been experiencing a lack of power in the 2500-3000RPM range, especially when upshifting.
The car still goes string in upper RPM band.

Using OBDII computer, if I reset all adaptions, the car runs great for 2-300miles. Then I assume the computer has stopped using tables and trying to use what it learned and goes back to misbehaving.

I have tried a new bypass value. 1st an aftermarket from Detroit tuned. That did not help, in fact it felt a little worse. So I went back to a stock value.

I'm at a loss. Is this a supercharger wearing out symptom?
Vacuum leak somewhere?
No codes from computer.

 

With no codes it is not easy to figure out. G3 is a shop in Raleigh and the owner Chris is a MINI owner.

The BPV may be wearing out as well, how good are you with wrenches?

 

Real good with wrenches.
I replaced my clutch 2 years ago.

I could try yet another BPV.

I've heard of G3. I will have to contact them.
Thanks!