I replaced the speedometer in my 96 Accord, as the old one was jumping to 20 mph and sticking there. I purchased a used one that was working when they took it out of the other car. Now, in my car, it works sometimes but not consistently. This one will sit on 0 mph and then just jump up to whatever speed I'm going. It seems to work better when the car is hot - like it's been sitting in the sun. Then sometimes, after it is working, it's just stop and drop back to 0. Any ideas?