1992 WT PICK UP 263,000 MILES HAD NEW HEAD GASKET INSTALLED VALVES LAPPED AND TUNE UP IT WAS DOING IT BEFORE AND DOES GET BETTER WHEN TRUCK WARMS UP, BUT STILL CAN HESITATE AT TIMES. WHEN COLD YOU HAVE TO FEATHER GAS PEDAL TO TRUCK ACCELERATING, YOU CAN HEAR TRUCK MOTOR POP THROUGH THROTTLE BODY BUT WILL CONTINUE TO SPEED UP
Check fuel pressure. Specs are 9-13 psi.
You might also check the throttle position sensor with the engine shut off. It has a plug going into it aside the throttle body. Once you unplug it you will see three prongs the plug connects to. Using an ohmeter see if there is a variance in resistance between the center prong and each outer prong as you advance and let off the throttle. I don’t recall the spec, but you’ll be able to see it if it is working.