1989 Dodge Dakota STALLING- Is it the ECM

V-12 engine?

What brnad of fuel pump did you use?

Anything other than OEM, I would get a pressure gauge for the fuel hokked up and run it to the windsheild and watch it when the problems happen to see if it is fuel related. ANy codes in the PCM?

You originally had specified a V-12 is why I asked about the engine.

While the ECM can be the problem, It isn't too common. Whne an ECM fails, there can be many different anomalies including your symptoms.

My experience with aftermarket dodge pumps is terrible. I have had this experience of an intermittant problems that are a nightmare to troubleshoot as you want to assume the pump is good because it is new. I am sure you changed the fuel filter correct? IF there is no test port, you need to splice into the fuel line to connect the pressure gauge into and test as I mentioned above. Having said that, sometimes you can listen for the pump hum
or lack there of when the problem is happening.
If you don't hear a hum, rap on the bottom of the tank to jar the pump...(yeah, I know it isn't a technical way, but can save time if the pump is intermittantly faulty.)

Testing must be done when the no start is present.

Test for spark when the problem happens. IF you have spark, it will greatly diminish the odds of an ecm. The PCM control both spark and fuel....as does the ASD relay.

I know you want to go down the ECM path, but I wouldn't jump to the end of the line first. Start at the basics. It gets expensive and frustrating to leap frog over the basics.

Questions? I'll help as best as possible. Intermittants can be a real hassle, but we can get through this.

Two other unscientific but helpful methods are the tap test. The asd relay and the ECM can be lightly tapped to see if it stalls when running or starts after tapping during the no-start period. A wiggle test of wires at connectors of related components may uncover the intermittant problem source.

One last thought at the moment is if this is heat related...that is the stalling and no start only happens after X amount of time. a suspected component can tested with a hair dryer to raise it's temperture into a fail point or removed and put into the freezer to cool it quicker.

In conversation, I learned a few things that might help. Check the wiring harness 4-6 inches back from the power distribution center under the hood. Look for corroded splices that feed ignition and fuel. Cut open the protective loom on the harness and be looking for corrosion.

If this doesn't pan out, then continue.

Also, I had heard of the pick ups in the distributer causing your symptoms.

The thing you need to weigh out is testing the better, more convenient or safer way? Often guessing is the more expensive way. Just wanted to drop that thought in there with this particular case.

So. You can do some simple quick things, if you are not in an unsafe area when it happens. Use some carb cleaner to narrow it down. That is, Spray it in the throttle body to see what happens when you crank it. This will at least isolate the lack of fuel as being the sole source. If it fires, then you narrowed it down to the fuel pump.

A spark tester may be valuable like this as well to identify spark loss.

Use a hair dryer and heat up the Distributer some before you run it and see if it is having an effect.