Original thread here:
https://dodgeforum.com/forum/2nd-gen...like-crap.html

So my first step was to remove the cat. Sawzall the thing off, and what do you know, already gutted! So that might explain the post cat O2 sensor code. I thought maybe it would explain the trashy sounding exhaust too. So I started it up with no exhaust, same sound! It almost sounds like their is a plastic wrapper stuck in there. I may need to record it to explain. Maybe it is just that it is running rich or something. I know it has always sounded rich to me (and at times black smoke at idle).
I welded in a piece of straight pipe.
Next on the agenda is the plenum, O2 sensor, 180 tstat, tune, maybe a coolant temp sensor? Think this sound will go away? I am mainly after better performance and mileage, but to me this sound is telling me something isn't right.

BTW, codes from original thread were:
P0138 1/2 O2S Shorted To Voltage
P0442 Evap Leak Monitor Medium Leak Detected
P0455 Evap Leak Monitor Large Leak Detected

 

Post cat O2 sensor has some issues. Shouldn't make a difference in how the truck runs though. (and that code is NOT caused by the missing cat..... that's a wiring problem.)

 

Did you ever do a full tune up?
Black smoke at idle indicates a rich running condition as you stated.

Have you pulled any of the plugs to see what they looked like?

What is the performance like? Does it go when you want it too?
It could/might also be a sensor malfunctioning causing the pcm to send out more fuel.

Just me thinking thats all.
Hope anything helps.

 

Interesting, hopefully the short is in the sensor. I have it disconnected now, I will see if the code comes back.

I have not done a full tune-up, but that is what I am beginning to do. The engine actually runs fairly smoothly, no hesitation or anything, just majorly lacks power. Idle is sometimes rough, sometimes smooth (kinda alternates).
I think I pulled one plug a while back and it looked normal. I will start pulling some more.
I need to make sure I get the right parts, these trucks seem to be finicky on brand names, so...

O2 sensor - NGK
spark plugs - ?
t-stat - any brand or MOPAR?
If I do cap and rotor, what brand?

 

Stock champion coppers work fine.
As far as cap and rotor, get them with brass contacts, they last longer and give a better connection.
I don't know about he t-stat. I don't think it really matters, but test it before you install it. Use the boiling water trick.

Just out of curiousity, does it misfire when accelerating?

 

Never had it misfire! Actually, the wires appear to be new, but I have no way of knowing for sure. Fairly clean engine.

 

So I was messin around and I grabbed the wire boot on top of the coil. Got the crap shocked out of me! Just a sign that I need wires? Also appears to be some kind of silicone on the bottom connector.

 

It's a sign that you shouldn't do that again. And probably a good indicator that you could stand new wires. When in doubt swap 'em out.

The stuff on the bottom connector is probably dielectric grease, and it's supposed to be there.