91 XR2..completely stock, two times now, have lost all boost after being driven hard.(We are autocrossing this car).The first time this happened, after the car sat for two weeks It was back to normal. Saturday we autocrossed, and lost all boost, including the 90 mile drive back home. Today I have boost again, but only about 6 lbs max. the blow-off valve appears to be operating correctly. Maybe the wastegate sticking open? Thanks in advance for any help.