e207, I like the way you think. I actually thought you were on to something, but then I realized that if you were right, the trucks would spit codes from new. They would also continue to spit codes after a knock sensor replacement as well. Or maybe the sensor just gets more sensitive as it ages and spits codes on start up, but will still do it's job when running?? I don't know just thinking out loud. I will continue to check for codes (thanks to the scangauge always being hooked up!)and let you guys know. I'm keeping my fingers crossed that it was just a weak connection in the terminal that got scratched clean by removing and re-installing it.