codes P0021 P0011 keep coming up sometimes reader says pass but two monitors not on 2006 Hyundai Sonata

cars runs good oil light comes on with idle after warm- oxygen sensors changed- new oil - new oil control valves

Asked by for the 2006 Hyundai Sonata
Test actual oil pressure using manual test guage kit ... Suspect low oil pressure.... Possibly from engine sludge. .. Likely due to infrequent engine service/poor quality engine oil and oil filter.
Have changed oil twice also put cleaner any ideas what next
Read suggestion again.
Oil pressure is 14 would changing oil pump help
That should be enough oil pressure **with engine idling at normal operating temperature** .. However at this point vehicle presence is required for 'systematic' hands-on testing .. Too many details easily get lost in transition over the Internet! .. (**)
Thanks for your help