[SSSoon]

Would appreciate any thoughts y'all have on this one.

It started when I was at Summit Point, but happens consistently every time. Bring the car up to speed, 3rd gear, 5k rpm, mash the throttle and I get a loud rapidly repeating banging noise, the three yellow Stabilitrack-related lights come on, the Service Stabilitrack message pops up, and doesn't disappear for 30-60 seconds afterwards. While the banging is going on, my boost gauge also thrashes around and I have no ability to accelerate. Stops the second I get off the gas. Does not happen under gentle acceleration, only under hard acceleration, and only at 5k+ RPM as far as I can tell. When I take the car to my GM mechanic, he can find no codes that indicate any problems.

I did some engine datalogging and sent it do Ted Jannetty (thanks Ted!), who concludes that the engine is pulling timing to protect the engine because it thinks whatever it banging around is the engine knocking (but it is probably false knock).

At first I thought it was caused by a broken sway bar bolt (one bracket that holds the sway to the car was loose) but after replacing it with a hardened bolt, same problem.

I know some of you will suggest: Turn Stabilitrack off and see if it still happens. I might yet do that, but my first instinct is NOT to turn it off when the car is clearly having some problems and when reproducing the problem requires high speeds and WOT. I do not want to be that guy who ends up in the ditch because he disabled the safety system that was preventing the malfunction from putting his car sideways.

I work with a great GM tech who is going to ride along with me on Tuesday afternoon with his scanner hooked up to the OBD port to see if he can figure out what the hell is happening in real time. But between now and then I am just at a complete loss to figure out what's going on. Maybe a failing wheel speed sensor? I don't know what the symptoms would be of that...

Thanks guys

Pete