I HAD A SIMILAR PROBLEM. 1999 GS330 WOULD CUT OFF AFTER STOPPING, BUT NOT ALL THE TIME. TOOK MY LEX TO DEALER AND I THINK MY WARRANTY WAS OUT. NO CHARGE! AMAZED ME. IF I REMEMBER CORRECTLY IT WAS A SENSOR. I THOUGHT IT WAS OLD TRANS FLUID MAYBE. HAD IT FLUSHED. IT WAS TIME FOR IT BUT DIDNT HELP. IT WAS A SENSOR. DONT KNOW THE PRICE OR EVEN PART #. REP JUST SAID IT WAS A SENSOR. GOOD LUCK