My dad just got a 03 Duramax with 113K miles, i know that this year has a big injector problem but what else should he look for? Kinda as a preventative maintenance thing. Thanks.

Transfer case rub.

check for engine leaks and check colors of fluids and levels

fuel additive..........lots of speculation about this on if it helps injector life.

Hey thanks guys, will defiantly do that.