03 Z71 Tahoe

[69gmcc10]

If you saw a difference when you cleaned the MAF I would keep looking there. The MAF plays a vital role in the engine, it can cause a plethora of various codes including misfire codes and O2 sensor codes. There are several tests that can be ran to give you a hunch if the sensor might be bad that you can look up and run. If you do replace the MAF go new and dont be tempted by a cheap refurbished one. I bought a refurbished sensor once and it was worse that the one I was replacing and I hear that is a common problem.

I would also check to see if you might have a cat starting to fail. Run the engine for a few and see if there is a difference in exhaust pipe temp from side to side in front of the cat.