There are many solutions to your P0300 DTC; many cost zero dollars to fix. Go to the search box in the upper right corner and type in P0300 then just to the left where it says threads click google.
Start with the obvious , check battery and alternator output, check all fuel injector and coil electric connections as well as spark plugs. If you take a coil pack off the car look at the back of the coil for cracks. That will tell you your coils are getting pretty old. spark plus? wires?? etc etc High RPM problem...Check fuel pressure.

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