Ed, the hour meter on my 2006 also was resetting for no reason. I found a post here on the DP that GM has a service bulletin out for this problem. The GM fix is to clean and tighten the battery terminals. My terminals were clean and tight but I cleaned them and tightened VERY tight and the problem went away. Additionally, if I disconnected both batteries the HM also reset to zero. There is nothing you can do to avoid that reset. There is something odd about SOME of the 2006 ECMs. Last year I bought a used ECM (same p/n) and had John Kennedy reprogram it and it will not reset the HM to zero when you disconnect both batteries. ???????
*2006 Chevy, 3500, 4X4, DRW, (LBZ) D/A, CC, LT, 252K Miles, 19.5" Wheels, Mag Hytec Transmission Pan and Differential Cover, SS Grill Guard, Racor 2 micron aux fuel filter, 100 Gallon Aux Fuel Tank, using Edge Evolution, Predator Diablosport, Kennedy ECM tune, Fitch Fuel Catalyst.
*2006 Four Winds, Dutchman, 36', RV, D/A, 5500 Kodiak.
*1993 Harley Davidson, Turbo charged, Springer Softail.
*2007 Pontiac Solstice.
*2005 Jeep, Liberty, CRD (diesel).
*Full-timing in USA, see America first.
BUY AMERICAN or CANADIAN, NOTHING from CHINA .