Hello,
I have a 2000 F-150 2WD 5.4 with 3.55 gears. I was getting some pretty good mileage 15 city, 17.5 city/hwy, 18.5 hwy, with 235/70/16 tires. My wife and I decided to buy a travel trailer (4800) loaded. Shortly before buying the trailer I decided to go with larger tires 255/70/16 what a mistake. City mileage drop to 13, city/hwy 15.2 but hwy went to a incredible 20.3. This was tested several times. Then I hooked up the Trailer, I now have to take out a loan just to go camping somewhere, the first time out i got 11.2, the last time I took it out I got a 10.1 miles to the gallon. I have used K&N filter no change, injector cleaner no change. Do you have any Ideas? I change the oil every 3000 miles and the fuel filter is being changed this week I have about 27000 on the fuel filter, I'm going to go back to my fram filter to see if that helps.
I just cleaned my K&N air filter is there a chance I sprayed to much oil on it? The engine runs smooth, and has great power.
One other thing when driving on the hwy with the trailer it sounds like the clutch fan ingages for some reason. Boy is it load the only time I here it like that is in the winter when I first start up the truck.