I have had this happen a couple times to me but when I have driven my blazer up a long hill or under load, the engine temp is above normal and after driving about a solid hour, the engine will just shut off.
It will restart but only after about a 20 min wait. during this time I would attempt to restart the vehicle but I do not hear the fuel pump pressurizing. Only after the wait do I get the pump noise, which is fairly loud, but it does restart. During normal driving, it operates great.
My question is, does it sound like it would be as simple as the fuel pump needs to be replaced or could it be something more systemic? After vehicle gets hot (not like burn up the motor hot, just higher than normal from hard climbing), it is shutting down the fuel pump or just shutting down the vehicle?
Any ideas or suggestions onthis?

 

bad coolant temp sensor it sounds like.

 

Have your fuel pressue tested, although based on oyur description of hte noisey fuel pump its about to go.

another option and could be the cause of your problem is the ICM, early signs its about dead is failure when hot. Once cool it works like normal. Good news is that most autoparts stores can test it. Make sure to put new grease behind it. The grease aids in coolign it down. So does th heat sink it is attached too. Got any exhaust leaks on the passengers side? They could be heating it up too.