On average I get about 300-320 miles on a full tank of gas on my 2003 Dodge Intrepid 3.5L; I currently have 120,000 miles on the engine, and use Lucas Oils in the engine and transmission. I have been testing the Lucas Fuel Treatment for the last 12 full tanks of gas (approximate 3900+ miles). Before I started using the additive I averaged about 20.5-21 at best, miles per gallon. The 1st three tanks using the additive, I was able to get between 22.1 – 22.5 MPG :); to see if the additive was the cause, I continued to rotate using the additive between tanks, 4th no additive, 5th with additive, 6th without and so on; what I found is when NOT using the additive, on a full tank, I average 20.9-21.2 MPG; when using the additive, on a full take, I average 22.1-22.5 MPG. Not only did I see a positive increase in fuel exonomy, I have also seen a better idle, startup, and overall smoother performance from the engine. I am very impressed with the additive. Thank you -James Johnston