Posting for another member this is his dilemma.

It is a 93 Elantra 1.8 DOHC with very stubborn CO, HC and NOX failure.

Pre cat loaded mode CO .6% HC 220 ppm NOX 1750

Post cat loaded CO .5% HC 200 ppm NOX 1500

Limits CO .5 % HC 90 ppm NOX 650

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