1993 Buick Lesabre stalls and dies

My engine has died twice on me. Once in the driveway as I hit the brakes and has stalled a couple of times while driving when coming to a stop. I hooked up a fuel pressure gauge and it read 42 psi so I changed the fuel filter. Then I hooked up my code reader and it gave me a history fault of IAT and I changed it. No change, though this time when I watched the fuel pressure gauge, the fuel pressure increased when the engine stalled. The engine rpm dropped to zero then the engine rpm came back up. This has occured when the enigine is cold each time. Once the engine is warm and going I have no problems with it. Has occured during first runs of the day. And there is no warning before this happens. The engine runs smooth and accelerates with no problem, even after restarting it.