getting PO171 code after oil change and black hose not hooked to air cleaner. Related?

Question

Just had shop change oil. The mechanic did not hook up the big rubber hose going to the air cleaner and runs to the rear of the inline 6 cylinder engine after monkeying around trying to inspect the air filter.  Never had this problem previously.  Code showed up the next morning as the vehicle was warming up in park. Could this be the cause of the PO171 code?

Answer 1

P0171 Fuel trim lean Bank 1

Most of all causes for a lean code condition are vacuum leaks . Any type of air leak that gets past the MAF (mass air flow ) that is unaccounted for will cause a lean code condition, So yes this would be the cause for the CK ENG LT.