in the fall before i put my car away for the winter my tach started acting up. when i was at idle sometimes it would read at 0 rpms, the needle was literally resting on the stop pin. when i gave it some throttle it would jump up and read where it was supposed to when i was driving. i haven't really noticed it as a problem since i've been driving it again this spring, but now the problem seems to be worse. the rpms are now reading low, even when i'm driving. they seem to be about 1000 rpms too low. it's not a constant thing though, sometimes it does show the correct rpms. has anyone had this problem before? can the tach itself go bad or would it seem like something else? i have no clue