My Chief was running like a charm and suddenly in July it started sputter when I run at low throttle. It seems to accelerate and run at higher throttle fine. So far I have verified the timing. I have replaced the ignition wires. I don't think it's electrical. I have pulled the carb and checked the jet and made sure it was clean. I tightened the intake manifold nuts. The problem persists. I just had the engine stroked and have put less than 1000 miles on it. It starts fine. It just has the annoying sputter at low throttle.