Originally Posted By: WobblyElvis
My son has a 2008 Cadillac CTS with a 3.6 direct injection engine. 130,000 miles and no maintenance of any kind performed on the fuel system. Runs fine. If your owner's manual suggests some special service then follow that advice but if no maintenance is called for, I would do anything.
I've also got an '08 DI CTS with 140k and no issues. I do, at every oil change, spray a can of carb/intake cleaner thru the intake with motor running to soak the valves and do "some possible" cleaning. I figure it can't hurt and only costs $5 for can of cleaner.