no... the o2 sensor isnt what tells the pcm there a misfire.... you have actual misfires... you just need to find out why... look at the codes and check everything related to those cylinders like compression, fuel and spark ...

 

It's possible for the sensor to be bad, and not throw a code..... if it runs rich/lean enough, it can cause a random misfire problem, but, if you have a specific cylinder that is consistently missing, more likely related to a problem with that cylinder somewhere. (compression, injector, plug, wire, maybe even cap.....)

 

did you rule out the crank position sensor yet? if it was o2 related it would run fine until it warmed up enough to go closed loop mode.

 

O2 sensor is fine i just changed it. The crank sensor has been changed too and still no change. Just changed the MAP sensor on the front of the throttle body and still runs like crap. It doesn't sound much like a misfire, more like a loud pop and i can hear it echo in my cold air intake. Anyone know where this "heater/O2 sensor fuse" is? The problem that guy described sounds exactly like mine.

 

Pull the cover off the PDS and turn it over. I believe fuses are identified there.

 

im actually having the same issue, except it doesnt matter whether hot or cold, it just wont accelerate. same thing, tapping the pedal it will go.. im assuming bad cat for me, i think im going to buy a new one tomorrow and try that out. (buying online, wont actually be in for a while)

it has done this "popping" sound in the intake before - used to only be going up a hill/higher speeds.. after which CEL would flash (catalyst damage) - which leads me to think its the cat...

recently did my plenum fix, and it was blown out, had an etest done recently and failed horribly - cat is screwed regardless. so thats what im going to try.

ive also been told fuel filter might cause this, unfortunately for us (or me?) the fuel filter is built into the fuel pump and is very costly. -- for a gamble, id rather replace the cat i know is bad first. lol

 

ok new cat as well as new front of cat o2 sensor, truck runs great again.

again my truck would not accelerate unless i kept tapping the pedal, if gas pedal held down it would feel like i was braking and hear popping in intake.

hope it helps.

 

The older trucks don't have a seperate fuse for the O2 heater. The heater runs off the ASD relay. If your truck runs the ASD is fine but the power wire to the O2 sensor heater could be damaged/broken/corroded.