Try removing the air duct to the throttle plate. It will be the big black round thing at teh very front of the engine. Take some choke cleaner and spray it all over the plate on the front and back. Wipe the gunky stuff off with a rag or paper towel then put eh duct back on and start the truck. It may start hard due to the choke cleaner being sprayed in the intake. Then drive it and see if it still does the stalling.