Speedometer and Odometer Problems

[Paulmac201]

My 1987 Buick GN has the 145 MPH Speedometer. The MPH jumps around while I am driving and is not very accurate. It tends to stick on a speed for a bit as well (stays at 30 or 35 even though I am going faster or slower than that). Also, the odometer does not work, neither does the trip. Any suggestions? Do I need to buy a new one? Thanks.

 

['87 Turbo "T"]

Can’t help ya with the odometer, but for the speedo cable there should be a connection right by the brake booster.

You can try to lube it & see if that helps. Myself, I just bought a new one(one piece).

 

[KC87]

Once in a blue moon my speedometer while cruising will suddenly start to do the bouncing back and forth thing.
I've found that finding a safe place to back up say a quarter of a mile or better yet when it's on jackstands just run it in
reverse for a while eliminates it. Odometer works fine but the trip meter has a gear problem.