ok, last night im just crusing and then all of a sudden my speedometer needle just drops and sits at "0mph". so i come to a stop light and start to take off and its not going back up as i accelerate. so i gun it really hard and the neddle seems like it kicked back in place where it should have been. but as soon as i stop again, the needle goes limp. also once i got home the CEL light came on and was throwing code 17. not sure what that is or if its anything to do with the speedometer or not. just wondering if anyone can help me out?

thanks in advance