I just recently added two bottles of STP Gas Treatment (they only had the small bottles), and another of Fuel Injector cleaner.

Oddly, I'm getting some sputtering when I first start the rig up in the morning.

I don't know if the sputtering has anything to do with the additives (spark plugs are brand new, and engine just got new fuel filter, air filter, etc.), but it got me wondering if that stuff is worth adding to the fuel tank at all.

Thanks!

P.S. - Is their ANY validity to the idea of running a tank of Premium every now and then just to clean out the engine? I've heard equally convincing arguments that the idea is bunk.