Went for a drive last friday with a pal and wanted to show how cool the car was. Car decided to have a bad day and it felt sluggish and ran quite lean under boost and there was some popping and sputtering in the exhaust. Saturday I checked quickly for leaks and cleaned the earths and changed the plugs (NGK BP6ES) and the same thing. Depressing the gaspedal slowly does help and the car accelerates better. But putting it flat down ends up almost 5 out of 10 times the same disappointing result.´

I'm not 100% if the fault was there before while I've been driving it a bit like a granny

The old and new plugs (after a short drive) were covered in white residue (old were NGK BP6ET). Tested the compression and it showed quite steady 11 bars (160psi) for all cylinders. Fuel pressure measured 3 bars (44psi).

I changed the ICV valve before the drive on friday. Car idles and drives well under partial load.

I have ordered a new fuel pump (Walbro 255lph) and new spark plugs (NGK B8EGV).