Thanks for the advice. Disconnecting Mass meter has no affect, fitting of a previous mass meter (changed 18months ago) makes performance even worse - so fairly confident the mass meter is ok. Further diagnostic checks reveal that the boost solenoid activates between 3000 and 4000 rpm and power comes...

:P Congrats on excellent diagnostic software. Makes home maintenance more feasible, just like the days before cars were fitted with ECU's During last weeks snow I started to suffer power losses when cold from startup, which once engine revs were upto 3000, power would kick back in (interesting drive...