P0134 GMC - 2002 GMC SAFARI where is the O2 sensor

Question

I have a 2002 GMC SAFARI, sometimes we have a PO300 and some times PO134 CODE,
Can you please tell me where is the O2 sensor for this code(po134).
Thank you.

Answer 1

P0300 Random misfire

P0134 02 sensor circuit no activity detected Bank 1 Sensor 1