My 03 Gmc Savanna 2500 right now has 313,781 Miles on the 5.3 Gas Engine so far all I've done to it was a Altanator at 180,000 Miles and a Waterpump at 300,00 miles, Everything else is still as it was when it left the Factory, Including the Plugs and Wires, it is Serviced every 13-15,000 miles...