My rpm gauge and speedometer works when I first start driving then stops

After about 10 minutes speed am crank sensor have been replaced? The rpm and speedometer works while vehicle is cold but after about 10 minutes of driving it starts freezing up when you stop and start again it will go up jumping but won't go back down until you stop and then stops on like 5 or 10 mph same thing with th rpm gage it stops a little above 1