Code on 98 GMC

Got a P01 72 code system to lean on bank 1 would that probably be the O2 sensor on the drivers side manifold? There is four of them drivers side
manifold, pass. side manifold, one before converter and one after.
Thanks Mr. Bill

Got a P01 72 code system to lean on bank 1 would that probably be the O2 sensor on the drivers side manifold? There is four of them drivers side
manifold, pass. side manifold, one before converter and one after.
Thanks Mr. Bill
hey bill clint it could be a vac and or manifold leak

Clint, replaced the 02 sensor and light went off and the truck even runs better maybe I nailed it on the first shot.