I have a 2000 3/4 ton crew cab with the 5.7 engine. Sometimes the truck will be sluggish when I first start it and take off, it will stumble once or twice then it will run and perform normal for a period of time.It dosent do this all the time, the check engine light dosent come on, the truck has 141k miles on it and is 100% stock. The plugs wires cap rotor were replaced at 100k miles, I've also replaced the fuel pump and filter recently (pump went out). Has anyone else had this problem or know what may be causing this? I am guessing it could be the fuel pressure regulator but havent done any test to confirm this.