I have dual 4500s and I am having an issue where my egt/cht readings on cyl #3 goes from showing normal temps to both showing temps in the 100-200 degree area. Is this an issue where both probes are having issues or could it be that one of the probes is bad and the display is showing bad values for both? It seems unlikely that both probes are failing at the same time. And yes, the cylinder is working just fine. ;-)