my emissions light on 2002 Ford Escape

we've changed the spark plugs, the fuel filter, air filter, oil filter. I know the O2 sensors and cat could be a problem but what is the next thing that is likely to be the problem? I have 2 wks to get this fixed to get through DEQ.
it has 101000 miles.

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1 answer 1 comment
first of all before you replace any things you need to scan your OBD11 for codes to know what is wrong first. and drive the car to alow the PCM to complet the drive cycle if the light did not come back on you are good to go but if its comes on you need to reascan it and do the repair. let me know what happing please Thank you
Nazier
My son in law is doing the repairs. He is a mechanic. He read the codes. I've never replaced my plugs so he started with that. The light did go off but this morn it came back on. I'm sure he knows what he's doing but just thought I'd ask. Thank you. Juli