I don't always buy the highest quality gasoline - I often buy from Costco and I understand they do not have anti-wear additives in their gasoline like most retailers. If I continue to use this gasoline, how often should I add some fuel injector cleaner to my tanks, or is this unnecessary until I notice a problem?

Thanks!

I, too, buy much of my gas from Costco and noticed the engines of both vehicles began to run rough after about 20K mi. I ran a bottle of better fuel injector cleaner (~$6-7) through both my HCH II and Ridgeline and noticed an improvement. Some people also like to run a couple of tanks of premuim through their vehicels periodically b/c it supposedly helps to "clean out" carbon deposits, etc. but I'm skeptical of this and have never tried it.

I have noticed a big difference in FE from brand to brand. I like Shell, but Costco is rated well? Have had no problems with injectors. For what its worth, H

Here in the Bay Area, Shell, Chevron & Costco gas all come from the same refiner, Tosco. I have never had a problem with Costco gas.

The fuel may come from the same refinery, but each supplier of fuel(exon/mobil, shell, costco, etc) adds in their own additives after they obtain that fuel from the main holding tanks. This is why the different companies advertise that their fuel has (fill in the blank) as an additive to keep the engine cleaner and running smoother.