Ya so when im driving not all the time but often. My speedo needle goes up and down bounces back and forth. i will be driving at like 60 mph and it goes to like 50 to 60 to 45 to 60 you get my point. it does not do it at any certain time. i can get in my car a drive some where and it wont do it. but when i get back in it will do it. its wierd

i did do the vss mod years ago dont use it anymore but its still hooked up. not sure if that could be it .
i also tried to swap out a cluster with a tech awile back. it worked fine except the gas gauge doesnt go down only up so i took it out and put my old one back in.


i have a 99 2200 cavalier. got like 105k on it


any help is appreciated

oh some times when its going crazy i fell my car hesitate for a split second. and it doesnt do it every time the speedo is acting up. it fells like the car wants to die or something

Sounds like the VSS is dirty or needs replaceing. I believe it has a magnetic pickup and some metal shavings could be messing it up. Mine was doing this and shortly after the diff went out. When I swapped to a different tranny that problem has never happened again.

take it out and look at it. if its covered in metal shavings, well get ready for a new trans