1996 Ranger will need 30-40psi of fuel pressure to start and run.
Fuel pressure should hold for a few months, not minutes, hours or days.....months
So you have a pressure leak.
If you don't smell gasoline then there are 2 places for the pressure leak.
1. The Fuel Pressure Regulator(FPR) is on the fuel rail with the fuel injectors.
It will be connected to the Return fuel line and have a vacuum hose attached.
Inside the FPR is a rubber diaphragm valve with a spring, the spring holds the valve closed when engine is off, when engine starts the vacuum will pull open the valve and allow extra fuel to flow back to the gas tank in the Return line.
Engine vacuum is high at idle when less fuel is needed, and low when accelerating when more fuel is needed.
If this valve isn't closing all the way then fuel pressure is lost when engine is shutdown, if valve was deteriorating then problem would get worse and worse over time until it can't hold any pressure.
Also remove the vacuum hose on the FPR, check that there is no gasoline in that line, if so replace FPR.
2. Fuel pump has a Check Valve inside, it is basically a flap that is pushed open when fuel pump is on, and then closes tight from the 30-40psi back pressure when pump is off.
This holds the fuel pressure above 25psi when pump is off.
The check valve is part of the fuel pump not a separate part, so whole fuel pump must be changed if that's the problem.
If you are careful not to damage the Return Fuel hose you can put a clamp on it, pinching it closed, doing what the FPR should do.
Then put on the fuel pressure gauge and turn key on and off a few times.
If pressure is holding now then replace FPR, that's the leak.
If pressure is still not holding then Fuel Pump check valve is the issue.
This is assuming engine was running well prior to this problem, a fuel injector can get stuck open and leak fuel and pressure, but this would go into the engine causing very rich running and noticeably lower MPG.
Last edited by RonD; 02-11-2016 at 11:08 AM.