It's either a faulty VSS (vehicle speed sensor) or the speedometer section of your cluster has failed.
March, 13, 2010 AT 12:42 PM
The same things was going on with my civic. Try replacing the speed sensor but I am more than sure its your speed o gauge.
May, 7, 2010 AT 9:33 PM
I experienced erratic speedo with misfire codes and o2 sensor codes. Number 15 fuse -- speed sensor blown. If it continues there is a common problem with this model year. Wiring harness located below air intake mainifold chafed. A bracket below the manifold is rubbing on the harness. If it is not too late, you can electrical tape, liquid electrical tape, re splice or cover with wire loom.