hey mine did that too...although i have a 95 GST with a 90 4g63. I did the following bought new BISS with the O-ring(dealer) bought new O2sensor (dealer) checked all my vacum lines for leaks(none) cleaned the Tbody till i could see myself. adjusted the Idle speed like 1000 times blocked the FIAV changed the IAC on the tbody and lastly i changed the MAF and that did it it quit stalling and the idle surge went bye bye.. good luck with yours man it took me like a month or so. peace isaias