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I have a question about speedometer error on my '85 Cabriolet.
The speedometer is about 20mph fast at 40mph, and I use a GPS to check it. I have had 2 speedometers in it, and the results are the same.
I am suspisous that someone in the car's past has replaced the drive gear with one from an automatic,( mine is a 5 speed) and this has thrown the speed off. The final drive ratio for the automatic is 3:41to1, and the 5 speed is 3:67 to 1
Anyone have a thought???
Earl