Have you changed the PCV Valve? If it isn't clear and operating properly it could cause some idle issues. The EGR might be clogged as well.

Both are known issues on 3rd Gen Dakota's.

 

Thanks guys. Ill try that this weekend and let you know

 

IAC cleaning along with throttle body cleaning cured my rough idle in the same vehicle type.

 

Thank you i will clean them both this weekend. I purchased a volo chip and was wondering if anyone had any positive results with it. I did not install it yet.

 

Has anyone installed electric fans for the rad and pulled the conventional off the waterpump? seem like it sucks alot of power from the motor

 

There are quite a few threads on this forum that discuss converting the fluid drive fan to an electric (use the search function in the forum toolbar). You'll also find discussions on fan types, controllers, and even a schematic or two, and even though the conversion will save you an appreciable amount of HP, leaving the old fan in won't be a reason for your truck to run rough. Did you ever get it scanned find the code causing the CEL?