90300 mutiple cylinder misfire.

Hello, code P0300 alone is unusual because it usually accompanies other P codes related to specific cylinders. Plugs and ignition wires - with original or high quality parts is step one. Step two would be to check engine compression! (Perhaps that's a better first step!). Engine compression on one or more cylinders that is compromised would set a misfire code. Diagnostic test equipment used to do more specific testing is needed to drill down to the source of your concern. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops