I have the 3.55 gears with 20 inch wheel package and my speedo is off about 3%. The truck goes less distance/slower than is says it does/is. I have verified this with GPS also.
Also - the fuel computer in the dash is usually off by about a gallon. The truck uses more fuel than it says it does. I have been experimenting a little and found that if I just go to the next dollar when refueling, the fuel computer is closer than if I stuff the tank. I think the "extra" fuel I put in when I top off does not get counted by the computer?? Only problem is - with only a 25 gallon tank I have to stuff it to get anywhere!!!
Ford has some work to do with the gauges and senders. They are not very accurate in my truck.
Last edited by mowdoc; 01-19-2011 at 06:02 AM.