3M makes an injector cleaning kit, you detach the fuel supply line, pull the fuel pump fuse, plug the 'kit' adapter into the fuel rail, hook up the can of cleaner and start the engine, takes about 20 minutes to empty the can of cleaner/fuel.
I do it once year, borrow my neighbors and go pickup a can at the napa store.
The rest of the year I just add a LARGE bottle of Chevron Techron Fuel injector cleaner to the tank, NOT the fuel system cleaner, INJECTOR cleaner, there is a difference. I do this about every 8,000mi or so. I have started using SeaFoam and it seems to do a good job, I notice an improvement after about 40 miles or so, starts quicker, idles smoother. I also use valvoline synthetic fuel injector cleaner in the gold bottle, depends on whats on sale.