Flashing CEL is a major misfire. Could be caused by ignition issues or could be a plugged/faulty cat.
285 isn't your tire height it's the width. Would need the sidewall ratio as well as rim size to have an idea on tire size, but regardless the EVAP issues are more of a nuisance and less to do with how its running.
The oil pressure is concerning though. Oil pressure should go up when you gas it, but it being low enough to lock the oil light is not good news. Your bottom end likely needs attention. It's not if something happens but when it's going to happen.