Once in a while I get a PO171 code. Car run fine, so I see the reason, and put it out. Replaced map air , and two Bosch upstream sensors. Light still comes on once In awhile. Brought to dealer, and they say with those 02 sensors they don’t see voltage change like they should. Can’t find oem sensors, and is this really the problem or a process of elimination. Thanks I’m advance for your help. John