I have a 2004 4x4 5.8. I always was suspicous that the speedo was not accurate. I just bought a GPS system and it confirms that my speedo is reading about 3 miles higher than it should.

I went to the ford dealer to see about getting it calibrated and they said that 3 miles over is within spec. I couldn't believe that they could not calibrate it. It only has 22,000 miles on it and is still under warranty. Has anyone else experienced this ? Also are the speedo and odometer driven off of the same component. If so then I am also travelling less than what is being recorded to the order of an extra 5 miles per one hundred miles. Thus at the 36,000 I will only have traveled 34,600. Should still have warranty available to me.

What are your thoughts,

Thanks

 

Well look on the bright side, you won't get pulled over for speeding as easily.

 

Mine is more off at higher speeds (as expected)... when my speedo says 70, my edge says 66 and my GPS says 64

 

There is a 1-3 mph error in the Speedo(spring tension). It's a analog device

 

Hey, where did you get a 5.8 engine? None of the rest of these guys got one! T-I-S-N-F!

 

+ or - 3mph is in spec and normal for Ford. Way too many variables to ever have it 100% accurate.

 

Mine Is +2 to +3 mph over actual. That seems to be the norm for most everyone.

 

Why is my Chrysler minivan dead nuts on???? Even on the rental Chrysler is on? Why cant the needle be on with Ford? I just don't buy it.... Has anyone ever checked a different Ford model????

 

How do you know this?

 

My 02 F250 and my 06 F150 is about 2 off for MPH. I had heard that from all other forums that this is the way that it was. I don't really care one way or the other. I think that it is a strategy by Ford to err on the side of under instead of over (read less than actual speed). My company 06 trailblazer is right on.

Just look at the way GM calibrates their fuel gauges. IF you can get 400 miles out of a tank of gas, you get 300 miles out of the first half of the tank and then 100 miles out of the second half. The gauge drops like a stone from 1/2 tank down. Its a calibration strategy to make you think that you get better gas mileage than you really do.

Ford has the spedo and the oil pressure gauge thats not a gauge.

 

The speedo is a little fast as stated, due to it being an analog device. Ford errors on the safe side to avoid lawsuits for a speedo showing a slower-than-actual speed.

The odometer however is exact. It uses the same signal as the speedo, but does not have the inaccuracies of the analog guage. The only speedos that Ford calibrates are on the police package vehicles.

 

About +2 here as well.

I have always noticed in all the Ford cars I've driven that the gas needle seems to stay at full for alot longer than, say, at the middle mark. Is this part of the tank design?

 

Mine was off +3 to 4 mph against the GPS. When I got my new (slightly larger) tires, my speedo and GPS are within .4 of each other............

 

Also, you can set the nmessage centre to display spped right from the PCM - This too shoud be accurate.
Search for the procedure ( hold down the reset while starting, release when TEST is displayed - scroll trough untl you see speed...) ...

 

Same here. I think the edge is the most accurate.