You want to disconnect the battery before disconnecting MAF. Than connect battery, after connecting MAF first. MAF is sensitive device, and we do not want to take any chance of causing damage. But also disconnecting battery for 20 minutes, reset ECM. Than engine relearns the signals from a clean MAF.Could the fuel filter cause only bank 1 to be lean? I checked the intake bolts today and all were tight. I could not find any loose vacuum hoses.
I sprayed some carb and intake cleaner on all the vacuum lines while running to see if I could hear the idle change and couldn't gear any difference. The clicking is mostly gone since the throttle butterfly cleaning, but the code still comes right back after I clear it.
It is only p0171
Both banks lean, is most often associated with fuel delivery. i.e. fuel pump, fuel filter, fuel lines, fuel dampen device, fuel pressure regulator, fuel pump resistor.
I'd go through FSM diagnostics tree on throttle body, checking motor and sensor. Also do a fuel pressure test.