88, 2.6, carb, auto, all stock Ram 50. Started bucking last night while driving at all speeds. Idled smooth in neutral or in gear at stop. Pulled plugs-all 4 were sooty, black. Cleaned plugs and shot carb cleaner down it's throat suspecting stuck choke. Ran great for a mile or so and bucking started up again. Runs fairly smooth under acceleration, the heavier the better but still bucks. Still idles smooth and revs fine with no load. Runs great for a mile with a shot of carb cleaner (the choke is open and is not sticking). Haven't been out to look at it this morning...yet. Ideas?