I haven't had the truck long. All I've done to it is exhaust and add a K&N air filter. It seems to hesitate whenever I accelerate hard from a stop or going into traffic. I have ran a bottle of the Lucas fuel system cleaner through it. Don't know if it's getting to much air or not enough gas or both. Does anyone have any suggestions ?

 

Pull the plugs, check condition or just replace them if you have no history on them.

It's where I'd be looking first.