Have the codes read by someone proficient with an OBDII scanner. Auto Zone is ok but sometimes their scanner doesn't give you the whole picture. It sounds like it may be a misfire but it's best to have it scanned
Is it ok to drive P
That's hard to say without actually knowing the issue. Get to a shop as soon as you can
Po300 is that bad
I think a P0300 is multiple random misfire. I definitely wouldn't drive it too much without a concrete diagnosis. It can be any number of things from coil pack(s), to spark plugs & wires, to fuel injectors, possible fuel filter or even the vehicles computer. Have it checked out asap
Looking for a Used Cavalier in your area?
CarGurus has 627 nationwide Cavalier listings and the tools to find you a great deal.
Search Chevrolet Cavalier Questions
Chevrolet Cavalier Experts