boost leak? please help

[benger83]

2002 wrx (stock): i had a misfire in cyl. 1. the car ran like **** (real rough idle etc) so i replaced the spark plugs and the coil pack. It didnt help. so i replaced the MAF and it seemed to work for the roughness but now when i accelerate it seems like my boost isnt consistant. If i put the pedal to the floor it accelerates rough but when it hits around 4000 rpms there is no more power and the boost gauge reads higher than normal. for example if i am in 4th gear going 40mph and i put the pedal down i can feel the boost hit and then die off and on then at 4000rpms there is no more pull. and the check engine light starts to flash until i drive regular again.

[EJ257]

boost leak?