smarksel Report post Posted August 24, 2016 My tachometer needle intermittently swings wildly, then settles down again. When settled down, it is accurate. It seems to swing wildly (sometimes but not always) when I depress the accelerator. When I release the accelerator, it goes back to normal readings. I have a 2001 Safari with a Cummins ISC 350 and an Allison transmission. Any ideas? Share this post Link to post Share on other sites
dickandlois Report post Posted August 24, 2016 Smarksel, My first thought would be to check the connection of the sensor. They are exposed to the road elements and there could be a corrosion issue. You did not mention any check engine issue, the sensor signal is also used to time the engine. A Cummins tech could check for any codes and also look at the connections. Are you a member of the Cummins Power Club? Should you need some work done on the coach, members ship helps pay for parts and labor. Last I knew it was 10%. Rich. Share this post Link to post Share on other sites
