Same thing I've always heard from mechanics. I sell auto parts and most mechanics will tell you if your injectors need cleaning it will have to be done with pressure through the rail. The over the counter fuel injector cleaners are good to add from time to time to help keep the injectors clean (once they have been cleaned) IMO.63AKDN said:All of the mechanics I know say that you are wasting your money if you just add a bottle when filling the tank. The best way is to get the injectors done at a shop where they disconnect the line and spray the cleaner directly into the line so they say.
Some people have told me that they have had noticeable improvements after adding a bottle in the gas tank. I have bought stuff over the counter and added it to the tank as well, but can't say that I've noticed any difference. A few bucks compared to about $100 is worth a try though.