Could Misfire Codes be related to O2 sensors?

[jgray]

My 100 has about 229K miles now and recently started running what I best describe as rough. I have extra coil packs and shuffled them around so not a coil pack problem.

I am throwing the following codes - PO300 (random / multi misfire detected)
PO302 - cylinder 2 misfire
PO304 - cylinder 4 misfire
PO306 - cylinder 6 misfire
PO308 - cylinder 8 misfire

Prior to this happening my check engine light had come in showing a O2 sensor code. I replaced one and another appeared. I hooked up my code reader to check O2 values and I can only access information on Bank 1 - sensors 1&2 which read identical. I cannot pull info from Bank 2 on either sensor. I am assuming Bank 2 would be the side of the engine where cylinders 2,4,6 and 8 reside?

Here is the strange thing - if I clear codes or unhook battery for a few minutes the truck drives great but eventually the check engine light will start flashing and stay on again and all the misfire codes return.

I'm considering replacing all the O2 sensors thinking it may help especially since I can't read anything from Bank 2.

Any opinions or suggestions would be greatly appreciated! This is really frustrating!

 

[jgray]

Come on 100 gurus - I know someone has some good advice.

My local import shop looked at it and is recommending another motor. Since it runs fine for quite awhile after codes are cleared I'm leaning towards something electrical possibly....

 

[crimsonaudio]

Pretty sure O2 sensors cannot use misfires, though misfires can damage the o2 sensors. I'd pull the plugs to the corresponding misfires and see how they look.

 

[Sandroad]

Bank 2 O2 sensors are on the PS, as are cylinders 2-4-6-8. The two key problems, misfire codes and no data from O2 sensors must be related. Are the wires to the Bank 2 sensors ok? Any rodent damage? Any reason to suspect water damage to the engine ECU? I'm guessing (really, guessing) that if you fix the O2 sensor data problem the misfire codes will also be fixed. I have not searched on MUD for similar problems, but you might start with looking for solutions to the lack of O2 sensor data. And the shop recommending a new motor is a hoot.

 

[spressomon]

Hmmm...misfires could emanate from fouled/worn plugs. Have you inspected the plugs? I do believe dirty/fouled misfiring fuel injectors could also generate misfire code(s). I'm at 232k and was advised by Robbie Antonson to pull my injectors and have them thoroughly cleaned and tested (hot cycle); not for rough running but as a good PM measure.

Thoroughly cleaned the MAF sensor lately (use MAF specific sensor spray cleaner)?

The battery disconnect/reconnect does throw a little wrench in diagnosing. I'm out of the water on all things ECM but wondering if it might be related given your symptoms?

If you have the FSM you could check the resistance of the O2 sensors rather than just throwing $400 at it...

 

[PADDO]

Bank 2 O2 sensors are on the PS, as are cylinders 2-4-6-8. The two key problems, misfire codes and no data from O2 sensors must be related. Are the wires to the Bank 2 sensors ok? Any rodent damage? Any reason to suspect water damage to the engine ECU? I'm guessing (really, guessing) that if you fix the O2 sensor data problem the misfire codes will also be fixed. I have not searched on MUD for similar problems, but you might start with looking for solutions to the lack of O2 sensor data. And the shop recommending a new motor is a hoot.

I'm with Sandroad on this - I reckon if you find the reason for no bank 2 O2 sensor data you'll rectify the bank 2 misfire issues. I've been thinking (while waiting for lightening to clear to go tarpon fishing) what's unique to bank 2 fuel/air/spark? knock sensor maybe, cam position sensor, open loop/closed loop lambda, something common to bank 2 O2 #1 and #2 like a defective ground? It's interesting that the problem clears with clearing codes then returns after x misfires are detected or y O2 short term/long term fuel trims fail their spec - suggests to me the engine ECU is leaning out or enriching bank 2 to compensate for bad or absent O2 data. Maybe pull a bank 2 plug or 3 just to see how clean they are burning. I'd be hunting for a bad ground, loose or damaged cabling I guess. Probably hold off on ordering a new motor for the time being too.

 

[jgray]

Well I took a chance and ordered 4 new O2 sensors off Amazon... Denso appears to be the OEM Toyota equipment and they were about $42/each so worth a try... They will be here tomorrow and I will install and report back...

Thanks to those that took time to read my post and provide suggestions. @PADDO - How is the tarpon fishing down in NC right now?

 

[PADDO]

Well I took a chance and ordered 4 new O2 sensors off Amazon... Denso appears to be the OEM Toyota equipment and they were about $42/each so worth a try... They will be here tomorrow and I will install and report back...

Thanks to those that took time to read my post and provide suggestions. @PADDO - How is the tarpon fishing down in NC right now?

That's a pretty good price for your O2s, it will be good to either fix your problem, or worse case eliminate a potential culprit and not worry about O2s failing for years.
@jgray we were out of Charleston, not much action for us on reds or tarpon unfortunately , storms and turbid water = no good. Damn Finetooth sharks aplenty though!