slows down
wolfie06
09-13-2007, 07:16 PM
My 1998 Ford Taurus will spedometer will go down when driving 55-60 miles an hour then will go back up. It never quits running, it just slows then when I hit the gas it goes back up. Any ideas on what this could be? :shakehead
shorod
09-13-2007, 10:16 PM
Welcome to the forum!
Does the cruise control work, and is the vehicle maintaining a constant speed when this occurs? Verify against your tachometer that the tach is staying steady as the speedo is dropping.
If indications are that the vehicle speed is remaining constant, it sounds like you may have a failing Vehicle Speed Sensor (VSS), especially if the cruise acts abnormally.
You could confirm the VSS concern by using a scan tool with a datastream mode, then monitor the Vehicle Speed parameter while the speedo issue is occuring. If the datastream parameter also indicates a drop, the problem is likely the VSS. If the datastream parameter remains steady, then the problem is likely in the instrument cluster.
-Rod
Does the cruise control work, and is the vehicle maintaining a constant speed when this occurs? Verify against your tachometer that the tach is staying steady as the speedo is dropping.
If indications are that the vehicle speed is remaining constant, it sounds like you may have a failing Vehicle Speed Sensor (VSS), especially if the cruise acts abnormally.
You could confirm the VSS concern by using a scan tool with a datastream mode, then monitor the Vehicle Speed parameter while the speedo issue is occuring. If the datastream parameter also indicates a drop, the problem is likely the VSS. If the datastream parameter remains steady, then the problem is likely in the instrument cluster.
-Rod
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