Speedometer Trouble

Well, thanks guys for all the help. I'm going to disassemble the entire operation and make sure the speedo mechanism is clean and the cable is not kinked. I did lube the cable in the sleeve and install it correctly with no kinks or bends, but better to recheck everything to be safe. Just for informational purposes, the speedo does not "bounce" as it were, what it actually does is go right up to between 20 and 30 MPH while the car is barely rolling, and I do mean BARELY!!! Thanks again all for the good advise, Geof