Unusual performance

[Leon 9-5 Aero]

Hi,
2001 9-5 Aero manual, std software, with larger intake pipe and 3" downpipe.

Last few days noticed some unusual performance issues, accelerate hard, feels sluggish, view turbo gauge, sits at 3/4 in yellow, then all of a sudden kicks to usual full power, gauge sweeps into red zone.
Sometimes it won't give full performance til i come completely off throttle then reapply.

Once today, whilst doing this, engine check light started flashing away for about 30secs then went out??

Want to get to bottom of this before I put the remapped ecu on.

[-big kahuna-]

Hello. it's difficult to say exactly what the problem is, but you should first of all change the sparkplugs to new ones (NGK BCPR7ES-11). If that doesn't help you can try with a new DI-casette and solenoid valve. Also check all rubber hoses in the engine compartment so that they don't leak any air.

ragards

Fredrik