I recently purchased several crown vics at county auction, 98's and 96's. All ran perfect, but both of the 96's stopped running. The fuel pumps has stopped working, so it's either a relay, a fuse, or the pump itself.
My car starts and runs fine .Yours may need a fuel filter or pump.
It could possibly be the timing belt. Chevrolet recommends replacing it every 60,000 miles.
is it just blaring and wont stop or it wont let you start the vehicle?
Call the person who repaired the car and tell them what is going on. But what you write above makes no sense. You say, "(wont turn over) (wants to start) by (wont stay running)" If it won't turn over, how does it want to start, and how can it be running in the first place? Did they replace the fuel filter. If not, they should have.
lack of fuel
Sounds like a plugged catalitic converter. When they heat up they block air from getting by and the engine will not run.
check ignition
It could be because its running out of battery
put gas in it!
Make sure the Car is in PARK, if it is in gear like Drive or Reverse, the Car won't start even if the battery and starter are fine.
car start and drives fine bu when its turned off it wont start until it cools?
I am not sure of the type of car. I had the same problem with a Chev Beretta. It would not bring up a computer code so I tried different things without success. I changed the computer and it fixed the problem and is doing fine. That worked for me. Anyway good luck