Speedo bounce

I have the same problem. Change the cable.

Yes, but it would require you to put an aftermarket part on your car, so you will never do it.

Ha. I'll betcha I can find an original.

Try undoing the speedo cable from the back of the speedo itself and squirt some silicone into the cable end, I had terrible speedo bounce and when I did this it worked perfectly and I've done 500miles and still no bounce and it costs nothing.

The bounce will return. Most likely the inside of the jacket has worn and catches the wire cable and developed a low speed bounce. The cable will break because of the worn jacket. The lube is a band-aide. Buy a cable. They are inexpensive, about $60. Easy to install. I did not have to remove the console, just removed the driver kick panel. Call your favorite Pantera vendor. Wilkinson's price was about $60

Speedo cables are coated with grease, and of course 40 year old grease gets thick, hard, gummy, sticky.

I squirted some WD 40 down the cable. WD 40 is loaded with solvents which soften grease. In my situation the bouncing needle went away & never returned.

Definitely worth a try.

Once you have tried the above methods, be sure to check/correct the cable routing to prevent any unnecessary sharp or high arc bends. This caused me some needle bounce...

I was not as fortunate as George. I pulled the cable. Cleaned the old grease off of the cable and cleaned out the jacket. the bouncing came back a few months later and then the cable snapped.

I agree with Pappy, check the routing and turns.