Ford Senior Master Technician here! First off, if the timing belt were off a tooth or two, the engine will run but be a REAL pooch, slow to rev and lacking power. A 2.3L in a 97 Ranger is a DIS system, so there is NO distributor to contend with. My guess is that the belt tension is too loose or, there is something making contact with the timing belt. There is a crankshaft position sensor behind the lower pulley that may be contacting the trigger window or the belt may be contacting the timing belt cover itself. Remember, this is a free spinning engine, there is no possible way for the valves to contact the pistons, if the T-Belt breaks at 6000 RPM, there will be NO piston to valve interference.