My truck was only getting 12mpg pulling my 25' fiver empty. It was ticking when cold, and "popping " when warm. I ran GUNK diesel injector cleaner through(no alcohol). It increased mileage back to where it used to be(20mpg empty on winter fuel) and no ticking or popping. I haven't used injector cleaner yet, and wasn't sure if I should. I use it in my gas vehicles when they idle poorly, have poor mileage, etc. and it works great. Has any one else used GUNK?? Is it OK?

 

Never used it before. Tried STP once, and had no appreciable difference. Nothing above the plugs, wires, cap, rotor, and fuel filter I changed on the vehicle anyway.