1999 I30
codes p1320 and 300?? Ignition Misfire and malfuncution.... something along those lines cant remember the exact wording.

Right now my car is sputtering and riding rough unitl about 40mph. I have changed the plugs, put in fuel injector cleaner and iso heat (in case it was bad gas). Any input would be helpful.

The service light is on and sometimes it blinks also...