I used to think this helped get more gas mileage and I put it in all my cars. But I don't really believe that anymore and the last couple cars I haven't used it and they run real well anyway. I mean it hasn't hurt any of the cars I used it on. It's just that other people with the same kind of car were getting similar performance without it. And some of the recent articles I've read are somewhat skeptical about it's claims and I have no proof that it did anything but cost me money for not much benefit.