My daughter was driving the car home, and it started running rough and it died. a friend limped it home (only a few blocks running badly). I put a new fuel filter on it next day and it ran fine for 30 minutes, we shut it off for about an hour then it wouldn't start . It finally started and it would run rough and die. It is throwing no codes and has the proper fuel pressure at the rail. Occasionally the week before she was having trouble with it dying at stop lights. Sprayed ether around looking for vac leak, couldn't locate any. Any Ideas would be helpful, thanks.

Welcome to the forums Mike.
3 things a car needs to run well, fuel,air & spark.
3.1 engine? Throttle body yes?
When was the last time you serviced the plugs, wires, or a tuneup?
Throttle body needs to be clean and Air filter too.
The IAC /MAF/TPS can cause starting issues as well.
The IAC (intake air control) controls the idle, & often gets mega carbon so cleaning it can help.
https://www.gmforum.com/buick-172/in...avenue-304014/
Just throwing out some ideas there...

Car had a full tune up @ 121000, a new iac at 129000. it has 152000 now. Also, it is a Multi port injection. What bugs me is that it is throwing no codes and has none stored. Thanks for any help! Mike.

How is your coolant level?

and next to follow would be .is the oil clean on the dip stick, or bubbly and milky color?

its likely the maf try giving it a couple whacks with a screwdriver while its running and see if the engine changes pitch