First of all, buy a pressure/vacuum gauge. They're about 10 bucks or so on Ebay with free delivery most of the time! It's impossible to test a fuel pump properly without one. The inlet and outlet check valves are the most common failure items on any mechanical fuel pump and a pressure/vacuum gauge is the only way to check their function.

I think you're on the right track, suspecting a fuel flow problem. I'd suggest adding another filter hidden under the cab out of sight of people who have nothing better to do than point out "That's not stock!"- - - - -like one of the 3" diameter metal canister filters Ford used for years on their fuel injected vehicles. Those things can trap a huge amount of debris and still keep flowing enough gas to keep the engine running.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!