Thanks a lot RSH. I think that is my problem too. How did you get access to the tach sensor and bracket? It looks like I have to remove a lot of stuff to even see it. Radiator, belts, vacuum pump, etc. I only bought mine in May of this year and the tach never did work right. Is the tach pick-up on the SD on the front of the engine or on the rear? I too read the threads on tach problems. But this is the first I've seen on this problem.