That speed sensor is often the problem. But consider this, as well:
Article No. 01-5-2
FORD: 2000-2001 RANGER
ISSUE:
Some vehicles may exhibit a rough idle, Anti-lock Brake System (ABS) warning lamp illumination, inoperative or erratic speedometer, Diagnostic Trouble Codes (DTCs) P0500, P0501, P0503, P1721, P0176, P1000, ABS DTC 9, RABS DTC 16, or a delayed or harsh shifting automatic transmission. This may be caused by water intrusion at connector C309 (2000 model year) or C340 (2001 model year) under the driver's seat.
ACTION:
Inspect affected connectors; clean or replace connector pins as necessary. Install new sleeve and boot assembly over -14401- connector (interior). Refer to the following Service Procedure for details.
SERVICE PROCEDURE
Verify water intrusion in connector C309 for 2000 model year or C340 for 2001 model year applications by removing bottom half (male) connector located on -14405- wire harness assembly under driver's seat, outside, beneath vehicle's cab. If water is present or pins are damaged, remove connector sleeve and perform the following:
INSIDE CAB
Remove driver's seat
Remove driver's door scuff plate
Peel carpet or vinyl lining back to gain access to top portion of connector C309F (for 2000 model year) or C340F (for 2001 model year)
F = Female Side Of Connector
Remove connector from floor pan by depressing locking tabs on side of connector
Remove cap from back of connector to gain access to the pins
Remove red locking wedge from face of connector
Remove each pin individually and clean accordingly
NOTE: IF PINS ARE DAMAGED BEYOND THE ABILITY TO CLEAN, OBTAIN NEW PINS FOR REPAIR. ALL PINS WILL REQUIRE SOLDERING TO WIRE FOR MORE ROBUST CONNECTION. REFERENCE APPROPRIATE PINS:
F67Z-14487-AA replacing silver finish pins (1.6mm) and/or E6DZ-14487-AA replacing gold/brass finish pins (1.6mm) and/or F6DZ-14487-BA replacing gold/brass finish pins (2.8mm).
When all pins are cleaned or replaced, install new Cap (1L5Z-14A541-AA) over existing connector 14A464
Insert all pins through new Rubber Boot (1L5Z-14A099-AA)
Install pins into existing connector (refer to the appropriate Electrical and Vacuum Troubleshooting Manual (EVTM) for correct pin positions)
Install existing red locking wedge and seat rubber boot to new cap
Insert connector into sheet metal (floor pan area)
OUTSIDE CAB UNDERNEATH VEHICLE/DRIVER'S SIDE
Remove cap from back of connector C309M (2000 model year) or C340M (2001 model year)
M = Male Side Of Connector
Remove white locking wedge from face of connector
Remove each pin individually, clean accordingly, and re-insert into correct cavity of lower connector 14A624 (refer to EVTM for correct pin position)
NOTE: IF PINS ARE DAMAGED BEYOND THE ABILITY TO CLEAN, OBTAIN NEW PINS FOR REPAIR. ALL PINS WILL REQUIRE SOLDERING TO WIRE FOR MORE ROBUST CONNECTION. REFERENCE APPROPRIATE PINS:
E7EB-14461-BA replacing silver finish pins (1.6mm) and/or F6TZ-14461-AA replacing gold/brass finish pins (1.6mm) and/or F6DZ-14461-CA replacing silver finish pins (2.8mm) and/or E5DZ-14461-A replacing silver finish (1.6mm Circuits 52 and 64)
Install existing white locking wedge and reseat existing cap to back of connector C309M (2000 model year) or C340M (2001 model year)
Apply dielectric grease sparingly to all pins
Slide sleeve over upper connector and lock-in place
Slide lower connector over sleeve and secure with bolt in connector - torque bolt to 4.8 ±0.8 N-m (42.5 ±7 lb-in)
After connector has been reinstalled, verify concern has been eliminated. Reinstall carpet or vinyl lining, door scuff plate, and driver's seat.