Please help with wierd throttle problem

[Dustyroads]

I bought my 92 talon tsi awd a few months back and drove it a little before finding a cherry 323 gtx that I had to have. I had it the talon sitting in my yard mostly while trying to sell it, only moving it to park it somewhere visible from time to time. Always started right up and worked fine.
Until now. Started fine, idled a little loopy, but it always did that, it has a fiac delete. Trouble started when I tried to drive it. On the first and only the first time stepping on the gas it revs correctly. On second and every subsequent use of the throttle it revs to 2500 and then falls back to 2000. No matter how hard or soft I press the peddal, same pulsing result. The boost goes to 0 and stays there. If I turn off the car and start again same thing, first application of peddal gets regular response, then nothing. If I hold down the peddal it keeps the revs up for about 20 sec, then falls back to 2500-2000. If I let out the clutch the car surges VIOLENTLY. Checked under the hood for disconnected lines or loose intake/boost leaks. Nothing obvious. Disconnected all connections I could get to, no broken pins.
What is happening?