97 GMC Truck fuel pump problem

I have an older (97) GMC Truck (5.7L k1500) that has been good to me until recently. I replaced the fuel sending unit/pump and all the lines up to and including the entire fuel injection system about 1.5 years ago.

Recently I have an intermitant problem where the vehicle will not start occasionally, especially after parking the truck nose up on an incline for a long period of time (1 day or more). There is plenty of spark so I tested the fuel pressure. When the key is initially turned on and the pump is running, the the pressure reads 62lbs (within specs). As soon as the pump stops running the pressure immediately drops to 55lbs and holds steady. When the truck is running the pressure stays around 50 - 55lb at idle. Is 5lbs enough to blame the fuel pump or could it be a fuel pressure regulator issue?....I'm on the fence.

Any thoughts are greatly appreciated! That's plenty of pressure. I would say it's still a fuel delivery issue between a sensor and the computer telling the injector to fire. Maybe even a crank/cam sensor. Since it's an intermittant problem, not neccessarily would the check engine light would come on.

Have you checked fuel/spark when it's in the no start condition??

I would run by AutoZone and have them check for trouble codes. They do it free. One might be stored in there. Thanks for the input,

I'll check for codes, no engine light is on. The fuel pump runs in the no start condition but I did not check the spark. Next time it happens I'll check that and double check fuel pressure.Car Repair Talk's forum.