"Everything I have listed began happening BEFORE the backfire - these were all changes (excluding the cat) to try and fix the problem."

You worded that weird and it's confusing.

The first part sort of disagrees with the second part. Did you, or did you not, have the backfire before replacing any/all of those parts?

 

Hahaha oops - I can see how you're confused.

I've had the backfire before and after changing the parts - so neither of them were the issue.

 

Okay good, that doesn't leave much more to cause it.

I know some people frown upon "in tank" cleaners. But...you might try some Redline si-1 or Chevron Techron and see if you can get anything with that. (it might help and it surely won't hurt)

 

I tried seafoam back in March - some in the gas tank, crank case and vacuum line but no help.

 

it took me years to figure that small block chryslers attract moisture to the cap cause the cap is next to the fire wall with a lid, hood over it. the big blocks are not as bad as small blocks, cause they are up front. but having a ignition system right behind a fan doesnt sound good, that will blow water on it. i have been plugin the the vent for about 6-8 years, no trouble.

 

Just puting this out their did you try a new tps. just a thought.

 

No I haven't yet - I was considering this before but when I have time I will check the injector in cyl 1 just so I don't have to be buying anything.

After doing a bit of extra research I found out that the EGR valve may be causing this, but after doing more research I found out that the EGR valve isn't easy to find on the truck, nor can I seem to find a reputable place to buy it from other than the dealer. I've tried Rockauto, 1AAuto, Prime Choice and neither seem to carry it for some reason.

 

To my knowledge the egr does not function at wot or idle. So the backfire should clear up if you floor it. With that said I don't have very much experience with the egr valve on these engines.

 

If it has a egr vavle (my2000 does not) you will find it in the back of the intake on the right side.

 

I almost heard the backfire in the video. Did it sound like popcorn and that it was coming from the intake? My ram 5.2 did the exact same thing. Intermittent backfiring and I would lose all power, engine never stalled but going up a hill was tricky. Anyway it was the O2 sensor. My ram had one before the single cat and one after it. The front one was bad but I ended up replacing both. After that she ran like a champ. To test them I would safely measure the voltage across them to check what they are reading. Should be about .5 volts or so, anything FAR away from that will run the engine too lean or too rich causing backfire. There are 4 wires connected to your O2 sensor, two for the heater and two for the sensor, I don't know which is which you just have to try the combinations with a voltmeter. Also the computer might not throw a code if it is bad so best to check with a voltmeter before spending 80bucks on a new sensor.