Availability of Programmer to Improve Gas Mileage for 2004 Navigator

Question:

Hello, My 2004 navigator4x4 is doing 8.6 miles per gallon in the city. Is it possible to change that and improve the gas mileage. I had a tune up 9 month ago, and got 12 miles per gallon after that, but lasted only 3000 miles, then went back to 8.4/8.6. Can you advise me?

asked by: Robert A

Expert Reply:

Based on my research, the average fuel economy for your vehicle is 11 mpg / city and 16 mpg / hwy. Because your fuel economy deteriorated so quickly, we suspect your spark plugs might be getting fouled. I would recommend pulling and examining your spark plugs to ensure they are not fouled with oil. If they are it would indicate that your engine needs work. I would also recommend checking your spark plug wires for damage.

We do have some programmers that would provide a very modest improvement of your fuel economy, but they are meant to be used on engines that are in good running order.

Once you determine the problem and have it repaired, the Superchips Flashpaq Programmer # SU1845 features a Mileage XS Save program level that would provide an average of .5 to 1.5 MPG increase in fuel economy.

The Edge Evolution Programmer # EP59YR you referenced is not a fit for your vehicle.

I have linked you to an FAQ article that contains information about performance tuners.

expert reply by: Jeffrey L