I got an electronics repair shop to replace capacitors and re-solder my tach and speedo because my tach was acting up.

Tach works great now....Speedo reads 23 when sitting still, goes to 40 when idling along, and stays at 55 anywhere from about 10-70 mph.

Has anyone seen an issue like this before? Searching just came up with a bunch of dead speedo/ speedo replacement threads.

 

Also, just to double check, there are two screws that attach the speedo motor to the small motherboard, and then a third attaches through the white plastic, right? That's how I had everything laid out, but its possible I made a mistake there.

 

And somehow the cruise control works. I'm more confused, but feel like it has to be something with the motor after the speed signal separates. Anyone with a better unter standing of how the speedo works wanna chime in?

 

Its possible that they pulled the speedo needle off, and didnt replace it properly. I would pull the needle off, drive the car (with a friend) at 50 mph and replace the needle at that speed. This should get you pretty close to recalibrated.

 

Figured I would follow up. Supposedly he never took the needle off (makes sense as you don't need to to replace capacitors). Since there's still a speed signal somewhere, I think one of the 4 connections to the speedo motor wasn't working.

So anyways...
I went drag racing Friday night (better to have a tach than a speedo), got about 10 1/4 mile passes (best of 12.03 at 120.1), and on my drive home, the speedo started working perfectly. I can't explain it, but it's not the first time I've had small issues that fixed themselves when I started driving harder. She wants to run... all I can figure

 

Spoke too soon, started it up today and was already going 40 mph...now I'm even more confused.