AFR misleading? Plugs tell a better story?

yellow rose said

3% isn't bad on a cold engine. Even a warm engine with that leak percentage isn't bad.

The 16% is not good. Where's the air going?? Could be head gaskets or something.

Click to expand...

Will do leak a test tomorrow. Pulled plugs #1 is black. Noise was from the front, was thinking water pump or alternator, but really don’t think they’re making this noise.