1991 Isuzu Pickup S 4 Cyl 2.6L
Starts then sputters and dies. there is what appears to be an "air leak" coming from the fuel pressure regulator. Plenty
The problem sounds like a vacuum leak. Check the hoses and connections for damage / cracks / leaks. Replace the hoses and connections as necessary. Any air leak to the fuel injector pressure regulator would cause an imbalanced mixture and the sputtering / dying of the engine.