hi, my 94 wrx boosts really strong when engine is cold, (only tried this to see whether this was the case). but after it has been running for a while it seems to flutter when you give it some hard throttle. very frustrating.. so far i have been told that it could possibly be the water temp sensor in the block by the inlet manifold. any ideas please... thanks rich

 

clean out the boost solenoid and hoses that connect to it ! try that ! and dont kick its *** when cold !