This could be a number of problems from a vaccum leak to a bad spark plug, to fuel injectors. But, in my F150 it was the Throttle body doing exact same thing. Dealer replaced it under warranty and ran like new again. Dont know if rangers have the same setup but if you run out of options it may be something to check. But then again F150 has electronic throttle so its probably different.
I usually start with the simple things: Fuel filter, plugs, clean MAF, check spark wires, etc.
1996 Ranger XLT V6 4.0 5 Speed Manual.
Last edited by 96Ranger40; 11-13-2009 at 05:46 AM.