Recently the tach on my 71 Bee started to not work on start-up. Then after driving for a while it would work. It always has been 1500 rpms too high when working but the intermittent has me stumped. Also, previously when shut down the needle would hover at 500 rpm. Now sometimes when I get in the car, I noticed the needle parked at just under 0. When it is like that I find that that is when it won't work on start-up. Do I have a current drain when the needle is at 500 rpm after shut-off? Is the blue wire that is attached to a clip and protruding stud coming out of the engine side of the firewall and outer fuseblock the tach wire?