1986 4 cylinder car just ped california smog, barely. NO (PPM) # were high 1175 & 1007 max is 1208 &1038.?

other measurements were ok. smog tech says in 2 years before I get another smog test to have my car sent to a test and repair and check catlytic convertor and egr looked at. what would they do to these parts, clean , repair or replace these parts. is this expensive. I usually change oil, air and oil filter. what can I do in 2 years when my next smog comes up so the NO(PPM) numbers go down. smog tech says gas mileage will get better if certain parts are checked out.