Firstest: are you getting a Check Engine Light (CEL)?
Secondly: Try running some high octane fuel. Some members report success with that but I've never had to.
Thirdly: Try running a bottle of fuel injector cleaner on your next fill up.
If that doesn't work, there are some other simple repairs that we can recommend. On the bright side, we may be able to help you fix it with out spending any money. I'm just starting with the simplest things first.