ive got a similiar boost issue, valves bypassed, SAI bypassed, been stage 2 mapped by big fish tuning and SAI mapped out, what i get is 1.5bar boost peak then drops to a bar then up to 1.4 then down to 1 bar then by around 5000rpm it will hold about 0.7bar which is a total pain!! it should peak around 1.5 and hold around 1.2bar to redline! any ideas? boost leak, MAF etc??
car is off the road for winter but im wanting to sort this issue before its back on the road in april!
Thanks.