I own a 1996 Dodge Ram 1500 ext. Cab pick-up with a 5.2 L engine, it has 125,000 miles. When travelling on the highway the engine of my truck sputters and lacks power or is able to go past 40mph. It has only happened two times and each time it has happen, I used gas from the same gas station. When I pull over and put in more fuel and gas treatment it's as if nothing ever happen, what gives?