Ok, I believe my factory tach crapped out, so I bought an aftermarket tach. It's an Eqqus brand. Worked fine for a little while, but I had it splice in with the original tach. Tuned up the car and connected the tach correctly, taking the factory tach out completely. Now, the tach works most of the time, but when I drive it and I rev it past about 4000, the tach quits working. I thought it was a loose power wire, but it's not. If I stop and shut the key off, the tach will work again. I do have an Accel HEI SuperCoil on it. I think that may be the problem, but I don't want to get rid of it. Just wanted a few ideas of things to look for. Did a search of the other threads, but I didn't find any useful info. Any input would be appreciated. Thanx in advance.