Running rich is likely related to either failing O2 sensors, or the temp sensor the PCM uses. Another possibility would be high fuel pressure, but, that's likely not the case, if you are still using a stock pump.

 

This is really bad news Flounder. All that work and you remain in the same position. Frustrating, I'm sure.

Only you can decide what course of action going forward is best for you. It's your wallet, it's your transportation. But based on the cleanliness of your engine compartment it would seem you (or somebody) would have a truck worth investing in. If it were me (my wallet, my transportation) I would find me a good, seasoned mechanic to look it over. That's what I'm doing for my current problem. Then if they cannot find the problem then it makes replacing the engine more attractive. Of course you have decisions about that as well. Where do you get another engine? Used, rebuilt, etc... Decisions, decisions. But it looks like a very nice Dakota!

 

I just scanned over the thread. Is it an auto or manual? I have to wonder if something in the trans didn't break or slip and that is what is affecting how it runs.IDK how that fit with the heads cracking. I guess those heads might have been cracked a while and the extra effort of the trans failing.... Too bad it doesn't run well enough a SMOG test can usually point to the problem if its in the engine.

 

The transmission is automatic, 46RH, rebuilt about 6 months ago. I think I’ll go back there, tell them what’s going on, and see if they have any ideas.

 

I think it’s worth swapping out the O2 sensor. I’ll do that.

The ECT is new, as well as the connector. I spliced test leads into the two wires. When it is running I get the 5v feed and a very low voltage on the signal to the PCM. When I first started it up again, I had a persistent ECT code. I thought maybe the coolant hadn’t gotten up to the sensor yet. Eventually I got the engine temp up to where the thermostat opened and the code went away.

I’ll check the fuel pressure. I’ll try not to catch the engine on fire again. It is a new fuel pump (either Delco or Delphi, can’t remember).

 

An easy test for the O2's is to simply unplug them, and see if the engine runs any better.

 

I replaced the O2 sensor. No dice. Fuel pressure is 42 and steady.

I drove it about a block down the street and back. It surged, lunged, and died coming back up my driveway. I’m leaning towards Onemore’s hunch that it might be the transmission. It was rebuilt last Sept. I’m taking it in on Monday to have them work on it.

I have been chasing an engine problem for over two months now. If it turns out to be a transmission problem, I may have to take an extended vacation in a psych ward.

 

On the other hand, if it proves it IS the tranny it will be a relief to finally pinpoint the problem.

Keep us posted.

 

And that's doing that on its own?

 

Well when I got my trans rebuilt (the a$$ exchanged it without telling me, I had matching numbers) It did not run right. Felt like an engine problem. I took it to the dealer and they kept it for 3 days and when I came to get it they would not explain what they had done. I almost started a fight they were so effing obnoxious about it. Charged me $100 and when I drove away it was working as it should have been. IDK what they did, if they called the trans guy and switched out another one or just changed out the fluid and put the right stuff in but I'm pretty sure my problem was always the trans. It drove so nice I almost wasn't still po'd when I got home.

Edit- on another note, you are missing the air intake hose from the air cleaner to the grill in those pics. It's worth it to get that replaced if you don't actually have one. Colder air coming in is better than taking in the hot air from the engine bay.