Engine stutters and seems to bog down

I have an issue that occurs when driving. In od the engine seems to want to die out. It stalls and stumbles along jerk in the truck violently. This also happens in park when you snap the throttle. New cap, rotor wires and plugs. I switched to high octane fuel and used injector cleaner. The problem happens when the engine is at operating temp. I consider myself pretty good with cars and trucks but this has me stumped. Any advise or direction would be greatly appreciated.