I installed an Autometer boost/vac gauge and it seems to work fine with the exception that it makes a buzzing or vibrating noise. It sounds like vibrations coming off the engine but I think I've ruled that out. At first I had it connected with a plastic line and there was no noise. When I switched over to a copper line, it started. No matter how I hold down the copper line, there is that noise. Any help or suggestions are much appreciated!