inspect vacuum lines for cracks. I believe this model has a idle air control valve that may need cleaned. some times the get dirty. also could very well be a throttle position sensor malfunctioning so check if its working or not. also test the fuel pressure regulator... just a list of parts to test or clean. they call cause similar problems before.
I had a cracked vacuum line running to the solenoid near the charcoal canister. That caused my truck to idle wild like that. I have a 94 B3000 (ranger 3.0 equivalent).
Have you checked on whether or not there's water in your gas tank? Water gets into the tank from sources like a hole or using bio-fuel consistently.
Keep guessing and wasting money. Perhaps by next year you could possible have "fixed it." Did you know that brands and models of cars are proper names? Ford Ranger is correct. One last thing. Mechanics repair cars. End of story.
I have a 1988 ford ranger 2.9 liter 5 speed and I can't figure out what the problem is. I crank it up and it works fine I drive for about a mile then it start riding rough like its stuttering and itll do it then stop and repeat. And when I'm stop it idles all wild and stalls out. When I'm driving it and it starts acting up if I cut it off and back on itll drive perfect for another mile the does it again. I've replaced distributor spark plugs and wires and coil pack. Everything is timed right.