X Mahout, two questions,
Do you always run with that big roof box up there?
And I see that your EX has the factory towing mirrors, do you know what gear ratio it has?

 

No, The roof box was just there for a trip. I’m not sure on the gear ratio. All the identifying stickers I can’t find. I’m going to assume it’s the original rear end, and contact the dealer to see if they can tell me by the Vin code. That is, unless you know another way to figure the gear ratio

 

this can help you decode your B pillar sticker to tell you what your diff gearing is https://www.ford-trucks.com/forums/1...l#post13558807

 

Check your RPM @ 65 MPH. 3.73 will be a tad under 2000, 4.30 will be almost 2200. With stock tire/wheel size.

 

I was lucky to get the 8 in town i was getting. I get 7.9 avg towing my TT. I can get low 14’s on the hwy if I drive like an old man.

Also, what is the octane rating you are using? Sounds like 87? I was down to 5 towing my TT here in IL. It took me a year of trial and error to find out it was the Ethanol in the gas that was killing my mileage. At one point with a slight headwind I couldn’t get over 55! My next fill up I went with 93oct and what a difference. Power and mileage came back! Then when I was up in WI I filled up with pure gas (no ethanol) and it felt like I was driving a truck with 50 more HP, probably less but it was that much better!!!!! I now run a tune from 5star tuning with 89 octane. And I am getting the mileage I posted above.

Ethanol sucks our V-10’s weren’t designed for it! I’m fact my engine was so lean my chrome exhaust tip turned blue!

 

The computer should be retuned for a different octane level. As I understand things at least. The technical guys can 'splain it better than I can.

 

Took a drive today to test the theory. Held 2200 at 65 with 285/75 R16. Gonna assume its the 4.3 ratio.