I had the problem the first I got the air working on my car every time I stop it would go to 60 mph then when I would start it would go back down again.. But my car hasn't done it since I figured water must have been getting on a wheel speed sensor. When I got home that day I did clean the conntticon to the wheel speed sensor on the pass front. Never done it again

It'* not necessarily a speed sensor. My dad'* 96 ciera started doing this randomly one day, except when there was any powered thing on in the car, like when you hit the brakes and turned on the radio, the gauge would go crazy. Know what it was? Poor body ground at the battery. It also took care of the (ABS) and BRAKE lights on the dash. I think there'* a ground pack under the drivers side carpet somewhere (am i right guys) that gets gunked up and needs to be cleaned. Wanna hear somethin funny if i rev my car really high in park i can get the speedo to jump too. Lol