97 import WRX, I have replaced MAF, sparks, HT leads and coil pack. Have checked and cleaned boost solenoid. But its still hestertating when boost comes in. The car runs perfect from cold no hunting or rough idle boost works fine its only after about 20 mins of driving when the car is really warm. Fuel comsuption seems bad too. About 180 miles of £37 normal driving conditions. Any ideas cos I am sick of spending money on this. Also car seems to drive a lot better when first started.

Thanks