Speedometer reading off by 20mph
04-11-2009, 12:11 PM
#1
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Speedometer reading off by 20mph
Hello All What a Great site.
I am driving a 2005 F150 5.4L Supercrew Lariat 4x4 5.5 ft bed 18"tires.
Problem is the reading on the speedometer is fine when I'm just running around town or normal driving. It's when I do any highway driving for after about an hour or so it starts to reading less and less as I drive so far up to 20mph lower then what I am actualy driving. I know Iam going the right speed lets say 65 or 70 because because my GPS tells me the speed iam going and I have driven by the signs that tell you the speed plus keeping up with traffic.
It seems to only happen with the truck has been driven for a while. I think it has something to do with something heating up because when the truck is cold or lets say cool it works fine.
Ford service told me all they can do is put in on the computer and if it reads ok then there is nothing they can do.
Any advice ,, suggestions,, help would be so greatful..
Thank you !
I am driving a 2005 F150 5.4L Supercrew Lariat 4x4 5.5 ft bed 18"tires.
Problem is the reading on the speedometer is fine when I'm just running around town or normal driving. It's when I do any highway driving for after about an hour or so it starts to reading less and less as I drive so far up to 20mph lower then what I am actualy driving. I know Iam going the right speed lets say 65 or 70 because because my GPS tells me the speed iam going and I have driven by the signs that tell you the speed plus keeping up with traffic.
It seems to only happen with the truck has been driven for a while. I think it has something to do with something heating up because when the truck is cold or lets say cool it works fine.
Ford service told me all they can do is put in on the computer and if it reads ok then there is nothing they can do.
Any advice ,, suggestions,, help would be so greatful..
Thank you !
04-12-2009, 02:47 AM
#4
hum. That's the only thing that I can think of that will cause it to me off by that much. Possible the owner before you had bigger tires and had it tuned for it and but the stockers back on without changing the tune back to stock. Just my .02