I would say not needed! It is most likely just the opposite (to much cleaning) WHAT? You see injector cleaning is a thing of the past since we now have ethanol fuels! Ethanol is nothing more than alcohol! The issue is as a solvent ethanol is much better at cleaning than gasoline could ever be! This is both a good and bad thing! The good part is that it tends to keep things nice and clean due to the high sloventicity of ethanol! The bad part is that it destroys gaskets, rubber O-rings, diaphragm, hoses and etc that are NOT alcohol tolerant!
My guess is that you had an injector that is pre-firing at idle feeding more fuel than required!
Mike -
