2001 Toyota 4Runner code P0303 cylinder 3 misfire

All spark plugs, wires and pcv valve have been replaced. Prior to this the engine idled rough and started using gas. The check engine, VCS and ABS lights all come on together intermittently and go off after awhile. Pretty much random.

After replacing the above, the vehicle is still running rough and throwing code P0303 cylinder 3 misfire. Any thoughts on what might be causing this? We have not yet checked compression or catalytic converter. Just starting with things that needed to be done first. It did originally pull code for the O2 sensor but that is no longer showing. We also replaced the air filter as it was saturated with oil, but dip stick showed full and we see no signs of oil leaks, hence the replacement of the PCV.
Thanks, this is my daughters college car and just need it to hang on for a few more months! This was purchased used about 3 years ago.