First thing that came to mind was bad gas, but it could be a clog in the filter or the fuel line.

Either way, I second what flyromeo3 suggested. I'm not sure if that model has a fuel filter in the engine bay, might just be one in the fuel tank... in which case it's more difficult/more expensive to replace.

Running on less than 1/4 tank puts extra stress on the fuel pump anyway so it's never a great idea, but I doubt it's the pump itself unless you never fill it above 1/4... even then I'd be surprised.

When you add some injector cleaner, I'd add that first, and then completely fill the tank with gas from somewhere you're confident you'll get good gas. A major chain like Shell or BP, for ex., is supposed to have higher quality gas, but the main thing is that there isn't any water in it. Most, if not all, injector cleaners will help if there's water in the tank, but if that doesn't help they also have products specifically for watered down gas.

I don't know that there's anything wrong with the gas in the tank of course, but those are the easiest and cheapest things to try first.