Fuel Additive

They do something, but if your injectors are really clogged, they probably don't do that much - a cleaning involving a system that feeds cleaner directly through the fuel system works much better.

Also, gas is supposed to contain injector cleaning additives to prevent deposits from forming. I believe this is required in the US, but maybe not in Canada. For that reason, avoiding cheap no-name gas is probably a good idea, as you don't know where it comes from or what additives it contains.

There are many good products on the market that will clean fuel system " as you drive " A slightly clogged injector, or gummy carburator will respond well to these treatments. A jammed shut injector, or filthy carburator won't flow well enough to noticably improve. I'd say cleaner is a good idea, I'd change fuel filter after burning up a tank of treated fuel, just to be extra safe. As for "cheap" gas, I doubt the EPA would allow the sale of truly bogus fuel. Some mechanics say cheap gas burns up valves. I use cheap gas, and have yet to have any problems.