Tire size.
Elder User
Joined: Apr 2012
Posts: 990
Likes: 4
From: Tamaroa, IL
I have a 3" kit and 285 tires and barely lost any MPG up until I changed out my plugs then it dropped. I am assuming it has something to do with the larger gap design of the plugs but not sure entirely. Anyway when I get new tires they will be bigger but the lost in MPG won't bother me much at that point.
Postmaster
Joined: Jul 2010
Posts: 3,743
Likes: 2
From: Henrico, VA
No I had my Ford dealership do it because they had the same price as me doing it after I bought the tools I needed and I am well aware of only using motorcraft plugs in these engines. The plug it self has a larger gap to help keep cross sparks from happening and bogging down the engine. I will find a picture of the new and the old to show what I am talking about. I have had problems with it sense the change and a bunch of guys/gals around here have talked about the drop in mileage after plug change.
Postmaster
Joined: Jul 2008
Posts: 2,565
Likes: 2
I just recently replaced the 255/70x17 tires on my 06 with 265/70x17's. The one size bigger put the speedometer and odometer to dead on at 60 mph according to the GPS. It ran a little fast with the 255's. Once I recalculated fuel mileage for corrected speedometer and odometer the fuel mileage was about the same. Mileage appeared to drop slightly with the larger tires, but when I went back and corrected miles traveled with the correct miles, the fuel economy figured out the same as with the 265's. So unless you are going to go up a lot on tire size, you won't notice a big change in fuel mileage.
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05rangerout07f150in
Brakes, Steering, Suspension, Tires, & Wheels
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Sep 29, 2008 06:32 PM
