I had a nice drive to the golf course in my SV yesterday; about an hour each way. The drive was a mix of country roads (some with too much traffic as it is tourist season here) and a scenic highway. The car ran great but on the way home while on the highway portion (early in my return trip), I noticed that my tach was bouncing around within a 1000-1500 RPM range. I was driving at a steady 60 MPH when I first noticed red it. Out of curiosity, I took it out of overdrive and the tach settled down to normal. I turned it on and off several times to be sure it wasn't just a coincidence, and it was consistent. It happened in both 3rd and 4th gear OD, although it seemed to be worse in 4th.
It is a Tom H rebuilt tach and has always functioned flawlessly. What I found especially strange was that it seemed to disappear by the latter half of the drive, although it was difficult to be sure, given that I didn't have any more highway legs and was mostly in 3rd. I did manage to get up to 50 or so and drive in 4th OD and it was steady. I can take it out again for another drive but wanted to get input first on possible causes. I have never heard of this happening before. Any ideas?
Thanks,
Jim
It is a Tom H rebuilt tach and has always functioned flawlessly. What I found especially strange was that it seemed to disappear by the latter half of the drive, although it was difficult to be sure, given that I didn't have any more highway legs and was mostly in 3rd. I did manage to get up to 50 or so and drive in 4th OD and it was steady. I can take it out again for another drive but wanted to get input first on possible causes. I have never heard of this happening before. Any ideas?
Thanks,
Jim