I have a 1994 pontiac sunbird with a 3.1 multi port engine. The car starts fine and idles with very little issues, I have let the car sit for 30 minutes or more with no problem other then a little variance in the idle. Heres the problem, when you start driving the car and it gets to temp and you pull up to a stop sign or light the idle will drop but will recover, this will keep happening, but shortly at the next stop or two the car idle will drop and the car will die, now the car will start right away again but as soon as you engage the car in gear it dies again, it will restart again and you can rev the motor so its getting gas but as soon as you shift into drive or reverse the car dies. After about 5 or 10 minutes it will shift into gear and you drive away for about 10 miles and it starts all over again. It has not put out a engine code, I have replaced the fuel pump and fuel filter and I have been told its my iac control, throttle postition sensor, fuel regulator even the catalitic coverter. When the car dies you can hear the motor like its diesling on, but it grinds to a stop, but always restarts, please help I dont know which direction to go.I am really stumped about it dying in gear but fine in park.