code po138

Question

my car sputters on idle and stalls

Answer 1

P0138 H02S (heated 0xygen sensor) circuit high voltage sensor 2

This code condition will not cause sputter on idle and stall out. This is a downstream 02 sensor or a catalytic monitor sensor, What can cause what you have  can be from a faulty MAF (mass airflow),or  leaking fuel pressure regulator that leak from the pressure regulator vacuum connection .A TPS (throttle position ) sensor  that is intermittent can cause this condition . As for now .disconnect the MAF if it idle bettter you may need to replace the MAF. As for the pressure regulator disconnect its vacuum connection if fuel seeps out, a fuel regulator will be needed.