my friend has a 03 hummer with the 6.0. first of all a week ago, the code 135 popped up, 02 sensor heater blah blah, and now when we went to leave for work, the truck falls on its face and dies sometimes and threw the random misfire code p0 300. i replaced the fuel regulator on the intake and replaced the plugs and wires. truck still misses and runs like crap. ran fine the night before. stinks bad of rich fuel mixture and new plugs already covered in soot. is there a link between this and the o2 sensor,or does anyone have any ideas? cats clogged? or maybe a dirty injector? thanks

 

Like the BLah Blah Blah code said. The O2 sensor is going out. Bank 1 sensor 1

I believe thats Driver side Front sensor. you NEED those.

 

werd!