i AM GETTING FAULT CODES P 0300, 0301, 0303, AND 0305, 2010 3.5 santa fe

Hello, "oil pressure problems" do not cause cylinder misfire codes directly. "Flushed engine" - meaning -- engine oil? I would highly discourage this practice. Why would you drop the engine oil pan before performing some basic diagnostic testing related to cylinder misfire? Have you checked the ignition cylinder? Have you done a relative compression test? A power balance test? Have you performed a manual compression test and leakdown? Checked for proper fuel delivery? Are you using a Hyundai GDS diagnostic tool? Are there software updates available related to cylinder misfire concerns as you are speaking of? If you truly have starved the cylinder head of oil, you'd have caused significant damage in the cylinder head with the dual overhead cams and journals, and you would have related noise. I would suggest you're simply not on the proper path of diagnostic testing here, and following the path you are suggesting could cause further concerns unrelated to your current concerns, not to mention by a waste of time and resources.