False speedometer readings

[Leverus]

When I got in my Sonic to go on my lunch break today I noticed that my speedometer read a few MPH just before I started backing out of my space. I park on a slight incline so I figured I just didn't have the parking brake on all the way and it started to move when I pushed the clutch. When I left at the end of the day I had the car idling in neutral for a moment while I put my things in the glovebox and I noticed it gaining speed. 0...1...2. I made sure the brake was on and I definitely wasn't moving. After a second or two it went back down to zero. I made a few stops on my way home and it didn't do it again.

Has anyone else had this happen?

 

[laborsmith]

Not just on the Sonic. Never thought about it before, but I sense it is related to the computer(s) cycling thru its start up cycle and may be a quirk that appears in many if not most contemporary computer controlled vehicles.

Laborsmith

 

[Eric Smit]

If you're really worried about it, just slide on over to the service department.


-Eric Smit

 

[Leverus]

If that's so I find it odd that it never happened before today. I'm just hoping this doesn't turn into another problem I can never reproduce for the service department

 

[laborsmith]

I have for years wondered how different persons can view the same event with totally different perceptions. It could be what I have noticed is not what you are reporting, but if it is I have not (and do not now) see a problem. But I am not you.

I have seen this happen on other vehicles, not just the Sonic.

Laborsmith

 

[CoHPhasor]

intermittent problems are the worst.
I've seen guys try to troubleshoot things in other cars for years on end replacing part after part.

The worst part is it's always something simple that is constantly overlooked.

 

[Leverus]

That's the frustrating thing with my car. The problems I have only show up once in a while and never when I want them to (at the dealer). I wish mine would do this every startup and always grind into reverse while shifting roughly so I can get it taken care of instead of just looking like a crazy man.