hello, i own an 05 evo VIII w/15K miles on it. everything was alright until my last fuel up when i purchased some injector cleaner. i noticed my cars idle is a little rougher than usual. are these products bad for the engine or turbo?
I've never used injector/fuel system cleaners. They are not "bad" for the car, but with all the detergents in fuel already, they are really not needed. As far as octane boosters, they tend to not raise as many points as they lead you to believe. Mixing in race fuel will give better results. As far as your ruff ideling, put another tank through it and see if it improves. If not it could be a nonfuel related problem.