172 Lean Bank 1 After Exhaust

rbrown

Registered User
So I get new exhuast put on and now I get bank 1 lean code 172 and bank 1 lean during part throttle code 181.

I have stock exhaust manifolds but had them put both O2's in the downtubes. Relatively new O2's.

Thinking maybe they dropped one. But I have noticed a slight exhaust leak on passenger side. Could that be?
 
First thing I checked. But if it was unplugged the CEL would stay on. It goes in and out.
I think the 181, part throttle code, is the one causing the that.
 
Got under it real good in the daylight. They missed about a 1/2 spot welding the bung on. So if it's leaking fresh air there I would imaging it could be a lean condition.
Especially since it comes on right when you get off the throttle.
 
Looks like the little exhaust leak at my O2 sensor was the culprit, throwing the 172 and 181 codes. No codes after getting is welded shut.
 
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