You could try some injector cleaner, or the GM fuel system cleaner, but those do a better job of cleaning the tank than the injectors.
It certainly could hurt. You could also remove the injectors, and soak them overnight in some cleaner. And as mentioned in the TSB, you may want to start using some of the "top tier" gasolines. For a good, thorough cleaning, the best is going with the pros, who disconnect the fuel rail and connect it to a machine to clean them out.