I have 94 Ranger 4.0 with similar symtoms: will stall sometimes after releasing accelerator or sometimes after shutting off the engine if I try to restart immediately it only cranks. If I leave it sit for 10 min. it starts OK. Sometimes when idling for no reason the RPM increases a little as if it was about to stall and the computer gives it more gas.

How did you finally fix the 93 Ranger?

Thanks.