found my exhaust leak - broken weld on the 3bolt flange connecting to the headers.

broken in my engine for about 250 miles so far. About to do an oil change.

running great for the most part.
But getting a CEL P0171 System Too Lean Bank 1.
and a couple of codes for O2 sensors. P0155

could they be related?
I put 4 new o2 sensors in it when i had the engine out. Maybe a bad connection somewhere?