My 09 f350 with the 12 valve cummins just started having trouble with the tach. It will run a few minutes fine and then start having a bouncy tach and battery light coming on. Last time I drove it today the tach quit completely coming home but works when starting it in the garage. It did the same thing a few months ago but only once and never had problems on restart. I've checked the clearance on the pickup and it's ok and moved the swap helper over on top of the fuse box instead of on the firewall between the engine and brakes. I've put around 4000 miles or more on it since the swap was made.