You shouldn't have to clean fuel lines. I know there are all kinds of stuff on the market that calls itself fuel line cleaner, injector cleaner, fuel system cleaner and on and on. Of all of the stuff I have seen and/or tried, Techron is the only one I recommend. Once you have the system cleaned up and functioning, and you use the car regularly, you do not need to "clean" the fuel system. Besides all of the usual additives in modern gas, with the high alcohol content any deposits will be dissolved. Dirty injectors are going to have to be removed and cleaned eventually, even Techron will not clean up really dirty injectors but it will improve it. As for your bad cold idle, there are a LOT of things that can cause that besides dirty injectors and vacuum leaks.
David Teitelbaum