Speedometer issue.
 

Hi, everyone............newbie here with a 98 Park Avenue with a couple gremlins. My speedometer needle is bouncing. Observations: When coasting, needle is steady. upon light acceleration, it will bounce from say 40-80 mph. Let off gas and pointer is steady. Also, sitting at traffic light, needle bounces between 0-40 mph. Odometer continues to click off tenths. Place in neutral, all this stops. Any suggestions would be appreciated.

Sounds like those still have the old speedometer cable between gauge and transmission? Possibly worn out or defective cable itself. If either end is accessible I'd try a lubricant, squirt in either connection or both if can get at. May smooth out......

I don't think any cables are used on this car. It has a speed sensor on the output shaft of the tranny and is run electrically. I was hoping someone else might have had the same problem and could help me narrow the problem down. If the speedo were cable operated, the needle would not be active when the car is stopped, let alone register miles on the odometer. I have ordered a VSS and will replace it at my next oil change. Hopefully, that will fix it.

Am sure your correct on that. Only thing was with the bouncing pointer it seemed more of mechanical than electrical trouble. Even that stuff is all digital display these days. And then there's the digital reflection of speed or other that projects in middle of windshield. Some don't realize it's there at least for 2016 anyways.

Yes, the Heads Up Display (HUD) was used on some cars. I don't think I would like it. I understand that the inside of the windshield of such vehicles is coated with a special film and is very expensive to replace. I wish all cars were still mechanical rather than electrical, as I can work on them. I have repaired many cable-driven speedos, so these electronic ones are a different world for me.

Roger that on the HUD. Do use it but more like seeing a bird splatter on windshield. Kinda look through it mostly, can delete though if it gets too bothersome. Don't know if that was an extra option or standard.

I don't think it was standard, unless maybe the Rivera.