So I got this 1999 Dodge Ram 1500 Van with the 3.9l V6. Stutters at random times like it running out of gas. Throws both O2 sensor codes and sometimes a random misfire. I have replaced plenum with aftermarket aluminum and gasket. Cleaned intake and throttle body. Replaced every sensor possibly associated with this that I could think of. Timing chain, water pump, PCM, ect... And still doing the same crap after all of this. I checked all grounds that I can find and even added another from the alternator mounting bolt the the firewall. I drilled out the cat in case it was clogged. Oh and my gas mileage is at about 12mpg.
Anyone with any ideas please help

 

have you did this from this post?
https://dodgeforum.com/forum/dodge-r...n-the-iac.html

 

have you tested the fuel pressure?

 

Does that include the crankshaft position sensor between the engine and tranny?

 

When I replaced the Plenum and gaskets I cleaned throttle body and everything. Also replaced fuel pump assembly. And replaced the Crankshaft Position sensor. A little update, I found a broken green wire inside the harness above the tranny for the O2 sensors. I fixed it and it hasn't shuttered yet but sensor #1 is still showing code. I bought good sensors when I replaced those but I think I am going to exchange that one again incase I got a faulty sensor. what is the OEM brand I should be looking at?

 

So right after my last polst I started the van to warm up this morning and it started spitting and shuddering right away on and off.

 

I drove it alot today in conditions that usually induce it to act up and nothing. But light is still on. And seems to get poor gas mileage still.

 

These symptoms could be due to a wide variety of problems but the two things I would check first:

Did you clean (or replace) the IAC? If you didn't, thats why it won't idle smoothly.

O2 sensors: the OEM brand is NTK (made by NGK). I have found that Denso brand 02 sensors will also work OK. On a Dodge magnum engine no other brand of 02 sensor is going to work right! Only NTK or Denso.

 

Amen!

 

So Yesterday I found one wire that was rat eaten and rusted apart on the O2 sensor. I fixed that and very little change like I said. So today when I got done with work I tore apart the whole harness above the tranny to check all those wires. Well looks like that rat hung out for awhile. I found three more wires same thing. Just fixed all those and took for a test drive. No hesitation, smooth acceleration, and the light hasn't come on yet. So I will cross my fingers and hope that done it. Thanks for the reply's. Now on to the next problem. I will start a new thread if I can't find any answers here already.