On two separate occasions (1/27/12 and 3/23/12) the vehicle was traveling 65-70 mph on an interstate highway and the engine stalled. the vehicle could not be restarted and was towed to the dealer. for the 1/27/12 event, the vehicle stalled out in the passing lane and i had to make it to the right shoulder. the dealer did not determine the cause after an exhaustive diagnosis. it also included driving the vehicle over 400 miles, most of them at a high speed, in an attempt to duplicate the problem. it did stall-out once, and the vehicle restarted after 30 minutes. the second event was a merge from one interstate to another with the vehicle stopping on an exit ramp bridge leaving little room between the car and bridge wall on one side and the exit ramp on the other. this resulted in the recommendation to replace the two fuel pumps - which i have in my possession. i do want to point out that in both events we were in great fear for our safety. i assume this is not a common problem, since there has been no recall of the fuel pumps. i did want to report it in case there is an emerging problem. *tr