I run a bottle of Techron about every 25,000 MILES. It will only help with the fuel pump/fuel system. Since we have DI (Direct Injection) in our engine this cleaner won't do diddly squat for our valves. Keep in mind that GM will try to sell you a 50,000 mile maintenance package where they "clean your system" It is a 100% ripoff and don't go there.
Thx for taking time to send this info. It's always helpful to hear from those with the same car. I find the 3.6 has been pretty good so far; no complaints, except for once when motor shut down by itself as I was taking a corner. It has never repeated and when looked at by the Dueck place they couldn't find anything wrong. Guess one of those weird wonders that 'happen.' Dabe