I try to keep fuel treatment in mine if I think about it when I drive them. I don't know if it really helps though. I only burn premium that doesn't contain ethanol (supposedly) in my Mustang and add Lucas octane boost to that as it is supposed to have a stabilizer in it. The other problem I have run in to with this ethanol based, highly oxygenated gas is how fast it will evaporate out of carburetors when the car sits for even a week or two. I have a Corvair Corsa with the turbo engine and it has the old carter YH side draft carb. I had to put an inline electric pump on it just to get it started after setting as the fuel is gone in the carb in a few days. The old fuel pumps on those Corvairs won't hardly pump enough fuel to refill a dry carb. I put the same inline electric pump on my Mustang with a bypass circuit so you can just hit the switch to refill the empty carb to get quick starts after it sets for a while. It's a constant battle....
