I PUT A BIGGER DOWN PIPE ON MY 89 TURBO SUPRA, FROM SCO, NOW WHEN THE TURBO SPOOLS UP TO 4 PSI THE MOTOR WILL SHUT DOWN IF U BACK OFF THE THROTLE IMMEDIATELY THE MOTOR WILL CATCH UP AND WILL NOT DIE BUT IF U STAY IN THE GAS IT WILL JUST DIE AND IT IS HARD TO START AFTERWARDS....IF ANYONE HAS ANY IDEAS ON THIS PLEASE HELP. I HAVE CONTACTED THE LOCAL TOYOTA DEALERSHIP AND THEY DON'T HAVE A CLUE.....THANKS FOR THE HELP

Those symptoms are normally either a boost leak or bad/tampered with o2 sensor.