My Truck makes some noise at 40 MPH?

What is your question?

I resently started using Lucas fuel conditioner in to the gas tank. Before it made that noise and now i use it! is it a bad thing that i use 1/2 a small bottle every 2 weeks on a full tank of gas. I need to know if puting to much lucas is harmful to the engine. or is it ok because on the bottle it says over treating will nor be harmful to engine.