Fuel Pressure Question

[maisonmays22]

I am currently experiencing issues with my 1988. When I start the engine, it runs/idles/revs in neutral great. As soon as I put a load on the engine it starts to run really lean and dies, it wont even idle after being in a load condition. A friend of mine claims that a the regulator is not allowing enough fuel to the 42lb injectors that are powering the 408w and running it lean. Thoughts?

 

[Mustang5L5]

What’s the fuel pressure under load?

 

[maisonmays22]

What’s the fuel pressure under load?

Im planning on hooking up a gauge to the pressure side tonight to see.

 

[JD1964]

Was the engine running good previously then developed a problem on its own, or did it develop a problem after changes were made or work done on it?