I Hope someone can help.

I have a 1991 Ford F150 351 E40D tranny 4wd with 123,000 miles.

I live in Alaska, when it gets cold and the truck sits overnight the speedometer reads 20-30 mph faster when I first drive it until it warms up, about 20 minutes.

I don't have ANY problems if the temp. is above about 25 degrees F.

The speedometer isn't jumpy, it just reads too high for awhile, any suggestions.

Thanks,
John

 

Hm... 1991? I'm thinking that it's a mechanical speedo right?

Chances are, with the weather being cold, some piece of metal has contracted (shunk) what's causing this to act wierd on you. Once it has heated up (usage or weather) it begins to work correctly.

Not sure what else to tell you as I live down here in the south and freezing temperatures is about as common as a one legged man in an a$$ kicking contest.

Tony

 

Hey did you ever figure it out?

Mine does the same thing when it is cold and works when it warms up inside the cab.

I havent done it yet but I think it is the cluster that has to replaced. It is a pin when it does that

 

If it's a mechanical speedometer, lube or replace the cable.