Upstream O2 Sensor 07 4.7

[ALLEGRO]

Getting the P0031 code. Says 02 Sensor, Bank 1 upstream.

I see the down stream on the driver's side, but not the upstream. 2 cats on each side, so where the heck is the sensor located?

Thanks ahead

 

[fourwd1]

Moved to correct section where you should get an answer quicker.