93 S-10 Blazer 4.3 CPI - Please Help

If not driven for a while it will start and run fine with maybe some idle issues but it doesn't die. When you shut it off you have a small time frame (half an hour maximum) to start it back up before it strands you for several hours. It acts like it wants to start, there are sparks, but it acts like it's out of gas when it's really not out of gas. After it sits for 3-4 hours it will start back up and it will run until you shut off again and the cycle keeps going and going!

Could this be the fuel pressure regulator? If it is where is it located and tips on how to change it.

If not what else could it be?

Welcome to AF.
Is this a code W engine?
I would start with a fuel pressure gauge taped to outside of windshield or outside mirrow.
See if fuel pressure drops or quits when it does it.
Post back your fuel pressure readings.
MT