Were you able to find out what the issue was on your dakota? Read your thread and just wanted to know the problem

 

airflow sensor? This truck doesn't have one. with the bog, I'm wondering about fuel pressure/pump issue....
your MPG makes me glad I have a V8.. my '96, 4wd one isn't quite that good but my '92, 2wd is better than you say you have, in that department, at the moment....
my last v8 Dakota before these current 2, a 93, I converted to a stick.... and on the highway it regularly got 20+/ I miss that truck and I miss banging my own gears.

 

I'd replace the timing chain (not sure if you did tldr comments), on 318s they're notoriously weak and if it's never been replaced there's a chance it's so worn out it's causing valve float