I had the same problem with my 96LS....after long distance driving, it would just stop if I slow down due to traffic or get off the highway for fuel.....I took it to the dealer and they can not generated the same problem after they took it out on the highway or get any error code...according to the ticket from the dealer..."ALL SPECS TO BE GOOD DURING DIAG.". Anyway, they replace my engine ECU under warrenty even after my car was already out of warrenty for a couple of years . My car had 69390 miles, and it was done last July. The part number that they replace was 8966150302...I also talk to the master tech. at the dealer and he told me that he had only encounter these problem a couple of time before me.....I suggest that you took it back to the dealer and have the work done under warrenty...Good luck.