Hi. i have a 98 dakota 3.9. The truck has been missing badly and stalling randomly, which is often accompanied by an exhaust backfire (exhaust). It seems to happen under any condition, hot or cold, sometimes it will do it when i first start the truck, other times it will be in gear going down the road and it will jerk, stall and backfire. Sometimes will go days with no problems and just happens out of nowhere. I get code p0351, ignition coil primary circuit. I have changed the coil, distributor cap, rotor, plugs and wires. It seemed like it was ok for a few days after I did all that then it started doing the same thing again. I am thinking it just had not acted up in that time. Its seems like about the only thing left that would cause that code is the pcm. I would just rather not put out that kind of money on a hunch. Not sure what else it could be. Thought maybe the pcm ground connections but I cant seem to get good information on where they are located. If someone could point me in the right direction it be greatly appreciated. Thank you very much!!

 

I think it's the cats, you need to buy a pair from ebay. Those are the symptoms mine had and they all went away. But, I still have a check engine light. You have to have an exhaust shop to weld in the bungs for the o2 sensors as well

https://www.ebay.com/itm/2x-2-5-Univ...72.m2749.l2649

 

How is your plenum gasket? Here is a link for the code you are getting. Note that it says vacuum leak(plenum gasket). Also you need to clear the code and reset the pcm.
plenum fix