[pete25r]

my bugeye does that sometimes too. I've probably got different mods than you though.

I haven't really looked at it cause it only happened a couple of times when I had to safely swing around a tractor trailer to catch an exit.

I think it's something to do with the boost control system. I've got a self-made tune(it sucks, needs work) GM boost solenoid, PNPed turbo, most of the headers PNPed, GS topmount and 3in turbo back. I'm planning on putting a manual boost controller in the mix so I'll have a hybrid boost control setup. That should make it easier to tune out the boost surge/ oscillation.

I'm not 100% sure though about what is causing it. My bugeye has been doing it for a few years and it ain't blowed up yet.

 

[pete25r]

I do have a boost gauge and logged it once or twice. Couldn't nail the problem down though, yeh still working on the "advanced setup".

The boost gauge would bounce up and down. It would go to peak boost then drop about 5 psi and bounce right back and would repeat until I got off the throttle.

I have had a few smaller boost leaks but I fixed those and the problem remained.

I've been away from home and my car for a good while though, almost 5 months, yeh work sucks sometimes.

I know it is kinda apples to oranges because I have more parts for problems to show up.
The biggest thing I wanted to let OP know was my car hasn't blown up yet.

Checking for leaks (both hot and cold side of turbo), doing some logging, and re-evaluate my tune is my planned method of attack. I am going to throw a manual boost controller at it at some point to. Matty said I had to or I was a punk... something like that anyway.