When I am parked its at zero but if i get up to 30mph or higher it just stays at 30, is there a way I can fix this?

anything?

what car do you have? model, year, auto or manual?

do you have any CEL codes?

help us to help you

search 'VSS' and/or 'vehicle speed sensor'

....fill out your damn profile for starters. Also, provide more background (i.e. did you have the dash/needles apart?, did this just start happening out of the blue?, etc.).

I just bought the car so I don't know if it is happening out of the blue

I have a 1998 Subaru impreza 2.5 RS. it is a manual

I just bought the car so I don't know if it is happening out of the blue

I have a 1998 Subaru impreza 2.5 RS. it is a manual ....the term "out of the blue" means something that happens suddenly or unexpectedly (i.e. if the speedometer was working when you bought and then at some point it began displaying the activity/problem you describe). However, if it's been that way ever since you bought it, that's another story.

If you haven't tampered with it at all, it could be any nubmer of things. Hopefully the previous owner didn't bugger with it and it is something like UkNuck describes.