Help a n00b out please. I have an 02 wrx wagon. My modifications include (motor wise) AVO 320 turbo with AVO solid response actuator, AVO 3" turbo back (w/ 1 high flow cat), AVO silicone intake, AVO TMIC, Vishnu 321 uppipe, stock airbox, STi injectors, walbro 255 FP, ghetto oil catch can.

I have a dyno tune by Shiv w/ EcuTek. The factory boost control w/ the Vishnu aluminum hose connector (w/ bleed hole) is installed.

This weekend I was able to put several hundred miles on my car. I noticed that at WOT I am getting severe boost spiking followed by oscillation of about .3 mpa. I was in 5th gear once with the AC on or off and when I held WOT the boost would climb to about 1.2mpa then come back down to .9mpa then go back up to 1.2 then back down for as long as I would hold it to the floor. I could literally feel the surging. I understand this is not good.

Then, when I was in 2nd gear and mash it I would get spiking up to 17psi on my 91 octane map which usually never yields more than 15.5 psi.

My question is what could be causing this? Is it the Vishnu connector w/ bleed hole, my ECU, the turbo itself (its only a week old), an exhaust leak? (I think I have a small one and gaskets are on the way for this weekend installation).

I am wondering what causes spiking or oscillation instead of holding boost steady? any information is appreciated