Why does my 95 Buick stall then won't start for a few minutes then run for days and then stall again?

try a new coilpack assembly ,,it worked for me I had a similar problem on my 87 Century 3.8l. My Cam Position Sensor was overheating which changed the voltage and kept the car from running. I diagnosed it by pouring some cold water on the sensor when the vehicle wouldn't start and when it did I knew it was that sensor. It could also have been the Crankshaft Position Sensor. I would have chilled it next to determine this. I would also test that the the Fuel Pressure is accurate. My fuel pump worked intermittently causing the car to be hard starting when hot. ( I replaced the fuel pump and then found out about the sensors.) Good Luck!