Hi all . Just wondered if any has had this problem ? Now done 1700 miles and mapped it. Map has been checked and all ok. knock is at 20 and O2 readings are spot on but if i open her up to and over 1bar she holds back slightly and is hard to get over 6k at .6 bar no problem and drives perfectly. Now i've also bought a new coil and swapped from cylinder to cylinder no change and replaced the spark plugs. Again no change! It's running 18g,550's, magnex full exhaust .The car is a 93wrx so the intake to turbo is 90degree and has a with silicon hose running z32 maf could the exhaust cause this? or the intake hose sucking flat? your input would be much help