Recently my speedometer hasnt been going back down to 0 when I come to a stop or slowing down properly. The tachometer works fine and the speedometer does also when I'm starting off or just cutting on the car but after about 10-20 mins of driving it won't go back down to 0 when I stop and always reads about 10mph faster than in actually moving. Needle still moves like it's getting input but just reads 5-10mph higher than I'm moving. Eventually goes back down to 0 when the car has been off for a minute. The transmission isn't working overtime like it has a problem, do I just have to replace my gauge cluster? I use a speedometer on my phone for now (very accurate).

 

sounds like the cluster to me. Luckily they're pretty cheap.