every time i go out to my car to start it, it starts to click very loud and fast but it wont turn over the engine. after a while, it finally works but only for a short time. i figured the battery was bad so i put a new one in with no improvement. so i went to the starter solinoid and changed it. for a day it would work great! have no problems starting so i figured i had fixed the problem. but then i went outside today and tried to start it and its back to its old ways. it sounds like the starter just isnt getting the power. could it be a bad starter? and one more thing, ever since this started happening, the speedo will rest at 20mph. it will go up when i drive but it will never fall back to 0. could there be a short?