I have a 90 ranger with a 2.3 and i had a similar problem. it turned out to be my EGR valve. it was raining hard one day and i went to the gas station for some smokes. i turned the truck off, went in, and when i came out it ran like s**t. i took it to a buddys house and he started jerking vacuum lines and plugs and when he unplugged the EGR valve, it ran fine. so i just left it unplugged. no problem since. i dont know if this has any relevance to whats happening to your truck but i had all the same symptoms. slow accl, smelled rich, idled rough? just an idea...
I'd rather push a Ford than drive anything else.
1990 Ford Ranger 2.3L