Ford: 1993 ford F - 150 straight 6, fuel pressure gauge, ford f 150

Question
Truck has a hesitation problem when on a load uphill if you give it alot of gas, doesn't do it if you give it a steady flow of gas. I have replaced distributor assembly,fuel filter, spark plugs,wires,cleaned injectors with sea foam.
  at a loss any answers?

Answer
You basically taken care of the ignition system,lets focus on the fuel system, check the fuel pressure on your vehicle at idle and at a load, watch the fuel pressure gauge while doing this.If pressure drops at load then the suspect is the fuel pump.
THANKS