Mitsubishi Repair: miss fire, miss fire, fuel injector cleaner

Question
i have a 2003 mitz eclipse and its started to miss fire after the gas station put regular fuel instead of prem. and ive tried everything except take it in so the repair shop could fix it what could it be?

Answer
Nick,
Simply using regular gasoline instead of premium should not cause your engine to misfire.  When you said you've tried 'everything', I'd be curious what that would consist of.  Did you replace the spark plugs and plug wires?  Did you check the fuel pressure and injectors?  Did you run all the regular gas out of the car and then fill it with premium again to see if that helped?  A bottle of fuel injector cleaner may help too.  If you feel you've truly exhausted everything you feel comfortable trying, I would recommend you take the car to mechanic to have it inspected.  You may just be due for a tune-up.
Good luck!