Hello I need help how to diagnose what is the problem with my gas gauge. I have a 2008 passat 2.0t my fuel pump had a crack on the top and was leaking my gauge was working fine but I kept disconnecting the the plug to the top of the fuel pump on trying to get a quick fit till my new pump came in then I noticed the gauge stopped working. I replaced the fuel pump with a brand new one think it would fix the gauge problem as well but it didnt. I start the car the gauge goes all the way up to full then when im driving it just drops back down to empty but the car is still drivable. Does anyone know what might be the issue???