The new IAC has not resolved the problem. The problem seems to be getting worse. I was wondering if it could have anything to do with the transmission because today when it did it I punched the accelerator all the way down and it took off. It usually is happening at slow speeds and usually on hills.
What are the other possibilities for such a problem? It's still backfires when it loses power with light belt chirping.

I tried smacking the cat with my hand and I didn't hear any bead rolling sounds.

I checked the serpentine belt and it looks ok. The tensioning pulley seems dry but seems to work fine, not much play at all. All other pulleys and idler seem fine.

I discovered someone previously put a fuse in a slot for 4x4 but mine is a 2x4. I don't know if this would have caused any confusion for the electronics or not?

I am going to check at night under the hood to see if there is any arcing from the wires.

Seems to me that when there is backfiring it is either too much fuel, bad fuel or water in the fuel, intermittent or weak spark.

Need more help to figure this out.

 

Just checked under the hood and couldn't find any arcing wires. Hooked up the ELM reader to the laptop and it showed a pending code for the bank 2 sensor 2 O2 sensor. This keeps coming back so I'm going to go ahead and change it.

Could the O2 sensor be causing the kind of problems I'm having?

While doing a real time monitor of the O2 sensors, when I rev the engine both the Bank 2 sensors exceed 1.000 volts at times. Does that mean both are bad or is that normal?

 

Usually a bad O2 can cause the kind of problems you are having like power loss and backfiring. It's odd that sensor 2 is showing a problem, those don't really do much of anything. They monitor the cat and that is about all they do. Even more odd is I read the service manual and could not find any specs for O2 voltage. I believe they are a low-voltage part though. I would go ahead and replace it and drive the truck for a few miles to let the PCM learn the new sensor and see what happens. If you have more than about 80,000 miles on the truck I would seriously consider replacing all 4 O2's. They get lazy around 80K and if only one is bad now, the others may not be far behind. Use NTK or an OEM Dodge sensor. You can order NTK online from ntk.com or sparkplug.com. Rock Auto or Amazon may have it too. NTK is the supplier for Dodge OE sensors.

Jimmy

 

So are you thinking it could be the cat and not the sensor?

I unplugged the sensor and the problem is the same. Should it make a difference?

I think the voltage for the O2 is not supposed to exceed 0.900 volts.

 

If it were my truck I would be proactive and replace all 4 O2's and be done with it. Especially if there are more than about 80,000 miles on the truck. That is how I usually approach a repair, like if one tie rod end is bad, I will replace both so I don't have to do it all again later. I learned that lesson when I replaced only my lower ball joints. 3 months later I had to take it all apart again to do the uppers. Lesson learned. I would start with all 4 new O2's and go from there. If the problem persists, you may need a new cat. I may be wrong about it but I think that because the #2 O2 monitors the output of the cat.

Jimmy

 

The symptoms your having sounds more like the TPS. (Throttle Position Sensor) Power surges and rough idle are key clues of the TPS going bad. The voltage should read between 4-5 volts with wide open throttle and with the key on but engine off should read around .7 volts. I would check that before I replace anything else. It's only a $30 fix if it is bad. Some people say to go ahead and replace the map sensor while your at it but my favorite saying, "if it ain't broke don't fix it"

 

Thanks mattoney, I'll check that out.

So SilverCC, are you saying the #2 O2 sensor would not effect the air/fuel mixture?

 

The tps at closed throttle is at .66 volts and wide open it goes to 3.85. Good or bad???

 

Id day that's a good reading. Voltage will be different from truck to truck but your close to the "ideal" number range.

 

Downstream O2 can affect the A/F ratio, just not as much as the upstream. Downstream O2's don't do much more than monitor output from the cats. That is why they last a lot longer than upstream O2 sensors. Just as an example I replaced both of my upstream O2's at about 85,000 miles. I am still running my original downstream O2's and they are still OK so far with 159,200 miles on the clock now.

If it were my truck I would replace the TPS and drive the truck a few miles so the PCM can learn the new TPS. I guess the closed TPS voltage at .66 is OK but the specs really start at .25 of a volt, so the wide open voltage would concern me. It should be closer to somewhere between 4.5 and 5 volts, the higher end of the spec is 4.8. Yours is in range on the low end but out of spec on the wide open end. I would replace it and see whether the truck does any better.

Jimmy