When driving my 95wrx the boost runs at 0.85 bar stedy through 1st, 2nd, when in 3rd, 4th and 5th at full throttle the car delays at about 5500 - 6000rpm, the boost gauge is going crazy needle jumping everywhere, this is not only annoying but the delay is p$%%ing me off, any help gratefully accepted

 

Is it like a misfire? cos although not properly described it sounds like a common coil packs problem.
When were they last changed?

I only say cos it is only noticable as the load of the engine in higher gears means teh charge is enough to blow the spark out, meaning no explosion, and hence no gases to maintain pressure in to the turbo.