E-Fans

[Longshot270]

Before you take them out drive a little bit aggressive for a week or two. I dont mean pedal to the floor but accelerating a little bit faster than you have been doing. I noticed that my mileage went up when I started giving more gas until I got up to speed then I would pull back the pedal to the point the power/speed are constant. I am also going off of a vacuum guage so I can get the cruising speed/pedal adjusted faster and more accurately.

I also know that the 1700-2200 is the most common rev range for my truck. All of the shifts occure about 1700-1900 under regular driving conditions. I usually see 1100-1500 after the shift though. It also looks like you might have installed them when they switch from summer gas to winter gas. That usually means a loss of about 1 mpg on my truck with the same grade from the same station. So I would leave it on there until summer for more even comparison. And fill at the same gas station. I can go to two different stations and get over 1 mpg better from gas station A compared to gas station B.

Bringing the temperature up to 200˚ might also help.

[Jackpine]

You most definitely want the engine running in the 200-205 degree range! Even 210 is fine. Your thermostat STARTS to open at 195, with the goal of holding the temperature above 200 for efficient operation.

- Jack

[88Racing]

Seriously:
Keeping your vehicle as close to stock as possible with the ignition system will get you the most mpgs along with the least amount of headaches. So stick with stock plugs and coils.
Custom tunes will help.
Your fan that you replaced with the efans should have been an electronically controlled one with an electronic clutch instead of a fluid one.
Don't forget to do the 30K maintenance interval checks also.
Peace!