For about $20 get a new VSS vehicle speed sensor and swap it out. It sits on top of the rear diff.
Otherwise, take it to autozone and have them pull codes for free. Let us know what the codes are and we'll go from there.
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BroncoJoe19
2006 Alt Fuel Jeep (electric)
'98 windstar 3.8L
'99 Crown Vic 4.6L
'90 Full Size Bronco 5.0L
I'm not a professional mechanic, take my suggestions with a grain of salt, or a cup of coffee 
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