Ok, so on an unrelated, or possibly related issue, just the pat few days it has showed up, and progressively gotten a lot worse. I just didn't want to start a new thread.

Between 2000-2750, I have a huge and I mean huge miss on 1 or 2 cylinders, while under load.

*backstory* when I had first started up my truck with the new headers and it all put back together, spark plug wire from either 6 or 8, can't remember which one, fell onto the header and Burt a hole, so I put on some liquid electrical tape and let it dry, seemed to fix the problem as it was grounding to the header*

Every since now it has been working fine with the "fix" until recently I found a literal hole, in either 6 or 8plug wire(the one without the already fix). The wire haven't fallen and burned, but I tried the same thing with the liquid tape just like the other wire, to no avail. It misses badly, and it's pretty harsh which leads me to believe it's a spark not a fuel issue.

If I floor it in that 2-2750 range, it catches up and accelerates u deer load as normal at foot to the floor, but anything not to the floor it misses and lacks power badly.

I have warrantied the new set of wires because the one that did not burn, failed under high temps I assume, and I'll see what that does when I get them here, but what would be y'alls opinions? Could it be a tps? How do you think I can make it run decent until, the new parts arrive?

 

Going to have to replace the plug wires, and see how it runs from there. In the meantime, test the TPS, and see if it is doing what it is supposed to. (analog meter is best for this particular test.)

 

So I had to unplug the battery earlier this week, to do some other work, and when I plugged it back in and went for a drive, this problem was gone. In the three days I have driven it now, it has slowly started to come back with the misfire problem. I'll be testing the tips tonight, but just wanted to share this info in case it was important.

 

I tested the tops signal, ground, and 5 volt ref and it all check out ok. What should I try next? I'm thinking of unplugging the o2 sensor and seeing how it drives, and if that takes care of the issue, mainly because this started competing up once I got the o2 fixed.

 

What brand O2 sensor is it?

If the wiring checks out..... that leaves the sensor....

 

It's a denso unit. I know our trucks don't like the Bosch ones.

Today I also reset the pen by unplugging the battery again, and oddly it did the same as last time. It fixed itself, but will most likely come back again.

I have two theories:

1. Overtime the pcm learned its values of the engine and what all they should be and what it runs best at, but when the battery is disconnected, it is reset and has to relearn its values again. My first theory is that whenever I dissconnect the pcm, it runs better because it's values are back to factory. It learns its values mostly off the o2 sensor, which hasn't been plugged in till now. Now that it can read the o2 sensor, it is able to lean its values. I bout a no name reman pcm off eBay, and my concern is that the pcm is not working correctly and causing issues with either the fuel system, and/or the ignition. This theory suggests that the o2 sensor I installed is good.

2. The o2 is bad and as the pcm learns it's values after being reset, its learning a obscured set from a bad o2, and Is causing issues with the fuel system.

I'm thinking I will plug in my old o2 and try that and see if it returns to normal. If not, I will take out my reman 5.9 MT pcm and put back my oem 5.2 MT pcm and see if there is a change there. With those results I should be able to determine whether or not my o2 sensor is bad, or my reman pcm is bad.

 

If the O2 is bad, then it should start running poorly about 2 or 3 minutes after startup....

 

That's the thing, it will run good for a day or two, like it's supposed to, and then slowly go back to missing, starting every now and then, to every time I hit the gas. I CAn the hop out, unplug the battery, plug it back in, and there it goes, running like new again.

 

So it is learning bad behavior, for some reason...... Would be interesting to run some data logs over the course of a few days, and see what changes from running good, to not-so-much.

 

How would I be able to do that? I'm guessing I'd need some special scan tools, as well as oem Chrysler tools because it is a obd1.

What would be your approach? Try a different o2 first, or try a different pcm? I have both the o2 and pcm available, so I'm not having to buy a new one, for now I unplugged the sensor and reset the pcm so I can drive and tow with it and keep the power.