Re: Code P0420
Autozone can tell you which o2.
The scanner will say either A, B, C, D as below or any combination of the A, B, C and D.
A: "Bank One, Sensor One" Which would be driver side upstream sensor. (Before the Cat.)
B: "Bank One Sensor Two" Which would be driver side downstream sensor. (After the Cat.)
C: "Bank Two Sensor One" Which would be passenger side upstream sensor. (Before the Cat.)
D: "Bank Two Sensor Two" Which would be passenger side downstream sensor. (After the Cat.)
Due to it being a 420 in the code, we already know that it is bank one, so rule out C and D above.
O2 code can also be thrown by:
Retarded Ignition timing.
Leaking Exhaust Manifold or any exhaust joints upstream of the O2 sensor.
Bad or faulty engine coolant temp sensor.
93 Ranger Splash. Standard cab. 3.0 v-6, 5spd.
Mods: New engine and trans. Cluster swap with tach. New headunit and speakers all around. 4x4 front valance. Led turn indicator mirrors. Crystal clear head lamps. Clear corners. 5" driving lights in Valance.
Mods to come: 'stang seats, explorer console, window tint, flowmaster cat back, some mild port work.