Gents, Out of the blue, my tac is now bouncing wildly from 0 to 2500 at idle and continues this same rate of swing as I increase the revs. I've looked for loose connections at both ends... and obvious kinks in the cable. Before I yank it out and back to John Marks... and ideas? Tac has less than 500 miles since complete refurb. Don B. PA 1823