1997 Buick Lesabre stalling out when hot outside

My sons 97 LeSabre runs and drives like a top most of the time. Twice now though over the last three months it has died on him. Both times the car stalling out has been preceeded by a high pitch whining noise that seems to be coming from the fuel pump. The first time, it would restart and run for a few minutes with the whining sound then die again. We towed it and let it sit a couple days and found that cleaning the MAF sensor may fix it. We did this and it worked.
However yesterday afternoon he and a couple friends ran into town, about a 20 mile drive, to run a couple errands. Drove around in town for about 30 minutes and it started the high pitch whine from the tank again and made it a couple miles across town before it died again. Pushed it around the corner to a gas station and parked it. A few hours later, my wife and I went to go get it, didn’t know if I would have to push it or tow it, but I turned the key and it started immediately with no whining noise, so I drive it the 20 miles home without incident. ???
The outside temperature yesteray was in the mid 90’s and humid, and thinking back to the first time the car did this, the weather and circumstances were almost identical? When used to go to work out, or to work, or just little drives around there seems to be no problem. The car has even ran this 45-50 mile round trip without incident numerous times, but at different times of day with cooler temps, and some lengthy waits between driving times.
Does this sound like a fuel pump or sensor that could be failing? And why would it only act up under high temp situations? Almost like it was vapor locked, it had plenty of fuel, and didn’t make a difference earlier in the heat even opeing the gas cap to relieve any pressure? Completely stumped here??

Sounds like a fuel pump bearing getting sloppy. Get a new fuel pump.

If the pump is whining, than you are lucky. The pump is telling you I’m dying and replace me before I leave you strnded.

I agree with the others. And, you are lucky. My 2000 Explorer’s fuel pump died without a whimper. It took testing a few things to narrow it down to the fuel pump.

I think everyone here is right and that the day you cleaned the MAF sensor the car would have started anyway. In cleaning the sensor…you allowed the pump to cool off and the pump was ready to work again.
Same with the day at the gas station. It just cooled off until you showed up and it was ready to go back to work.

Yosemite

Thanks guys. That’s the plan I do believe. Kid get paid this week, he’s going to pick up the pump and luckily for us, he’ll only have about a quarter of a tank of gas before we have to drop it!!!