Service Engine Soon Light

I'm assuming there weren't any other codes when you had it scanned. You need to get it scanned with live data when driving it. The sensors which effect the airfuel mixture are the mass air flow sensor, manifold absolute pressure sensor, engine rpm sensor,engine coolant sensor, throttle position sensor,intake air sensor and the O2 sensors which you replaced. You need to get readouts while driving for these sensors and see if they're in range.

usually the ses light only relates to emmisions and fuel and a majority of my friends have tahoe's and silverados with the same engine. therse are all the ses light problems we have had and how we fixed them.

1. if you installed a k&n air filter you need to clean your maf sensor with some carb cleaner because the oil from the filter cakes on the sensors.

2. if you changed your spark plugs with pre-set gaps you need to change them and set the gaps manually

3. if you changed your 02 sensors and still have the problem it really is your catalytic converters (this one happened to me)

*in my situation when my ses light came on, it was because i was running rich from my preset gapped spark plugs, once i changed out my spark plugs (3 months later) the light went away but it came back because i was running rich sooo long that it damaged my catalytic converters. i bit the bullet had them replaced and now its good to go.