I am at my wits end here, and I could use some help..

BACKGROUND: I have owned a 2001 Ram 5.9L Auto for several years now without a problem.. The only mods done were shorty headers, a 10x3 open element with K&N and cat back. These mods were all done prior to my owning her..

RECENTLY: I performed a tuneup. New Champion cheapy plugs, Taylor wires, Cap and Rotor, took TB off and cleaned it out along with IAC.. because it had a small miss under load... this tune up was done in July/August.. ran great... About three weeks ago, perhaps coincidentally at the onset of some cold, damp weather, it started 'the problem.'

At first, I found a plug wire (#7) had burnt IN HALF on the headers.. it fell down from it's routing. I replaced it thinking that was the problem.. apparently it wasn't.

Upon start up in the mornings, or after letting it cool down, even if only for 20-30 minutes, it starts up and seems to run just fine.. then about a minute in, it starts missing, I can hear LOUD hissing form the air cleaner, and it backfires.. it drops idle to 400-500rpm and acts as if it is going to stall, but never does.. if I hit the gas, she snaps out of it, but then starts again, until it's warmed up sufficiently (about a mile or two, or if it warms up for 20 minutes prior to driving) then she runs just fine.

I have checked my wire routing as I understand there was a TSB on it; rerouted, nothing. I am not sure where to even start and I dont have the cash to start throwing parts at it blindly.. oh, and it's not throwing any codes.

I have checked the search bar, along with a broad Google search and surprisingly, I have found SEVERAL threads where guys are having, I mean, word for word, the exact same problem on 5.2 and 5.9's. There has to be a common fix/explanation for it.. the problem is way to specific and identical in all of the threads.. problem is, the threads are started, guys give advise and comment, but then you never hear if the problem was fixed, or how.

ANYONE have this experience or know of a truck that has, and how was it remedied?!

THANK YOU!
Joe

 

I would look at the dist. cap and wires again. As well as the coil. It's a start, might wanna wait for someone else to show up too.


Also, Welcome to DF!

 

Easy fix: Pre-cat oxygen sensor. Get one from the dealer, or Denso or NTK brands only. The others (Bosch, et al.) quite often fail to work properly right out of the box.

 

Unreg, it does it when cold and the PCM doesn't read the pre-cat 02 when cold.

 

What about the IAC? And was the battery disconnected when you cleaned the throttle body?

 

dlyter.. the IAC was taken off and cleaned (along with the throttle body) a few months ago in the summer.. honestly, I don't think I disconnected the battery when I did it.. but then, if that were to cause a problem, why would it have waited a few months to materialize? ..it ran fine for the past few months since the tuneup in July/August..? If I had to guess, I would say the problem began about the same time the wire was laying across the header tube.. could that have caused the #7 cylinder to dump fuel into the exhaust, burning out the 02 sensor?

 

The O2 sensors are relatively cheap to replace.. Unless the plenum has been fixed I dont think I would spend the money on that yet..

Edit: Try disconnecting the battery for a couple of minutes and see what happens..

 

The PCM starts reading the oxygen sensor about a minute after a cold start. The OP's description is the textbook description of an end-of-life oxygen sensor failure, or at least would be if there were a textbook. There oughta be a textbook.

If there were, it would also state that about 15% of all drivers with this complaint are just technically savvy enough to point out that there's no DTC set for it. To which I always reply that if you wait long enough, much longer than most are willing to put up with the failure and longer than anyone should (for the sake of engine wear), the code will eventually be set.

Trust me on this one, young grasshoppah.

 

Yeah, I trust you, makes total sense. I stand corrected.
The thing that confuzzles me is why wouldn't it misbehave like that even when warm/hot?

 

..so were talking the upstream O2? ...pre-cat sensor? Replace with NTK? (Rockauto carries them I think?)