alright i have a 05 wrx with equal length headers, catless up pipe and down pipe. about 95k on the car and just recently in ANY gear you step on it and it will spool real quick and spike up to about 19psi which is no good, and then immediately go down to about 3-5psi then SLOWLY creep up if move at all. i checked all vaccum lines and clamps to and from the intercooler and nothing seems loose nor can i hear a hissing. Now there are several things i had in mind. 1. could it be the wastegate actuator getting a weak diaphram? 2. could the boost solenoid be failing?3. is it the turbo.
if anyone could help with some ideas i would be very thankful