hey guys am new to the forum. i am trying to help my brother out. he has a 96 wrx impreza wagon with an ej20 turbo motor.
the trouble is when you do a boost pull in like 4th gear the boost climbs to 14psi at about 4000rpm and it feels like you stomp on the brakes for half a second then it picks up again and does it again about 4500 or 5000. i really know nothing about subarus but i am familiar with turbo cars. to me what is happening is boost cut but you all might have a different idea!
what boost should this car be running?
I thought to start with the wastegate was stuck but i checked that and it moves fine. so my next thought was the boost control solenoid which we swapped one out from a wrecked car (yeah ok it may not be working either but the best we could for now) and it seems to be still doin the same. just above the boost control solenoid there is a little black box with what looks like a little air filter on it. what is that?
I am thinking the prob may be a vac leak. can someone point me in the direction of a vac hose diagram so we can do a vac job to see if that fixes it for us.