I have a 1988 Buick Century and it will start and run for 45 minutes then just

2.8 Multi port injection

Got to know how MUCH fuel pressure it has - in psi .. and IF ignition spark IS present - while engine will NOT start.

It had 50 PSI WHEN NOT RUNNING AND IT'S NOT THE ECM WE CHANGED IT THINKING IT WAS THAT BUT IT WASN'T hE ALSO REPLACED THE CRANK SENSOR AND IT STILL WAS STALLING WHEN IT GOT HOT.IT WILL NOT START UNTIL THE NEXT DAY WHEN IT HAS COOLED DOWN.WE TOOK THE BRAIN OUT IN THE GLOVE BOX CLEANED IT OUT WITH AIR AND PUT IT BACK IN BUT STILL DIDN'T TURN OVER.THE BRAIN HAS BEEN REPLACED CAUSE THERE WAS A STICKER ON THE BRAIN BOX STATING THAT IT HAS BEEN REPLACED.IT IS ALSO GETTING SPARK SO I AM PULLING MY HAIR OUT WITH THIS ONE!