This has been a long, ongoing problem. And it seems to be temperature/humidity related. I had this problem last fall/winter, but it does fine during warm or hot weather. I have this problem once it gets around 50 or below degrees.

It does two things. If the engine is stone cold, I can pretty much count on it not starting up on the first turn of the switch. Starter will engage, crank the engine, but no start. I will crank it for a few seconds, turn it off, crank it again, turn it off, wait, repeat until it starts. Sometimes when it starts, it will kick off and die. Sometimes it will backfire out the tail pipe, or out of the intake. When it does kick off, it is usually in a flooded like condition, and I have to work the gas pedal to get it to smooth out. When it starts, it more often than not will die if I let it idle. until it gets warmed up. And even as it is warming up, once the temp approaches about 190, it will sometimes die while I have it at a high rpm. Usually though, once I get it warmed up, like running it for 10 minutes, I can drive it.

However, and this is the second thing, I could be on the freeway, running at 60 - 70 mph, and it will die. Sometimes it will pick back up, sometimes I have to pull over to a dead stop and start it back up. It does this almost every day. If it is cold and dry, it seems to be less of a problem than when it is cold and humid.

Over time, I have replaced the coil, cap, rotor, and last weekend, the distributor. All were in bad shape. I really thought that the distributor would fix it. The old one had engine oil in the cap, and the rotor was lose and wobbly. I replaced the crank shaft sensor unit yesterday.

I've also replaced the starter and battery (last winter). Starter was shot and battery was the wrong size. I've replace the MAP sensor, and the TPS unit, and the intake air temp sensor. I can't think of the name of it right now, but I also cleaned the throttle body, and that unit that sits on the other side of the T-body from the map sensor.

Since I put the new distributor in it, the Check Engine light has not come on.

I read another post where someone mentioned "Auto Shut Down". I think this is what's happening when I'm driving it and it dies. It seems that if I let up on the gas after maintaining a constant speed, the chances are greater that it will die.

The only other thing I can think of is that there is some electrical contact that is worn and that the humidity shorts it out, or interrupts the contact. Or the PCM is failing. I don't know what else it could be. I'm in Arkansas, and we don't use salt on the roads. The under body is rust or corrosion free. So, I'm having a hard time thinking it is a wire. I did take it to a Master Tech shop, they could find anything of course.

I'm at my wits end here. Any suggestions, besides buying another truck?

 

Hello fellow 2.5 never had this happen to me but it sounds like you are doing the correct things.

One thing I didn’t see was did you check the Distributor Ignition Pickup and also check the connection for corrosion also check all the coil wires and connections to the coil for corrosion

I just noticed you have a new distributor so it should have a new Distributor Ignition Pickup

Sparkplugs are they OK

 

I just looked over your post again and suspect an O2 senser they are cheap I would just replace them anyway and they are easy to get to on the 2.5

How old is your cat? original?

How old is your muffler?

Back pressure in the exhaust system could do this

Your Dakota is as old as my 2.5 Dak at the 10 or 12 year mark it’s time to start replacing many things all sensors should be replaced and usually the complete exhaust system are things that are a must if you want a well running engine

The 2.5 Is a very simple engine nothing complicated about it the two things I said are your options

 

I was curious about that. I noticed yesterday that the donut ring at the exhaust manifold/exhaust pipe connection seemed to be gone. I was going to replace that and the O2 sensor, but, I was under the understanding that the O2 sensor was not read by the pcm until the engine reached operating temp. I'm sure the cat and muff are original. But even if the cat is stopped up, it should start and run for a bit.

While I was typing this post, my internet went down. I went to the parts store and they said there was two O2 sensors. They sold the Bosch brand, which I've heard are not very good. Is there a different brand than Bosch?

I need to get any error codes from the truck. But, the check engine light isn't on, so, I don't know if any are stored.

 

Thats true and why I asked about the cat and muffler

I installed the Bosch in my 2.5 upper and lower with no problems and they have been in my Dakota 8 months now But NTK is the OEM brand and most people buy them

I have replaced every sensor but the crank sensor in my 2.5 as well as a compleat new exaust system and she runs great.


As you can see I have modified my 2.5 a lot for better performance

A/C change out info here LINK

 

The original mufflers on these are monster tanks and tend to get rusted up inside I grabbed an all stainless steel muffler it should last about 8 years or longer and a magnaflow cat they are a good priced cat at only $90 and are supposed to be a high flow cat the shop that did it also replace all the tubing with a wider tube for better flow

 

If you haven’t done this I recommend a complete vacuum line replacement all your vacuum lines except the hard lines for the smog they are fine. I found most of my vacuum lines and elbows were close to rotting off the engine or getting hard as a rock.

Especial check the lines going to the side of the throttle body manifold they were the ones in the worst shape