I have a 99 expedition with a 4.6 full time 4wd. Will de using it to tow a car and trailer about 1000 miles. And I will be using it on other fishing trips and such with a heavy boat.I know I can do something with a computer chip or something to get more power and torque out of it. But is it a noticeable difference. I know that at times you can get better gas milage to by doing this, I believe?? Can anyone help give me some insight on this??? I sure would appreciate it. Can this motor take the trip towing car and trailer that far without pushing it to far???? Thanks

 

So long as you are within the factory towing limits, you should be fine.

Do you know what your rear-axle ratio is?
I may sound like a broken record, but rear gears play a big - and definitely noticeable - role in towing. Especially if you have a 4x4 with large, oversized tires.

Do a quick search, there's a few posts on how to determine what your rear-axle ratio is.