Having problems with your 1991 Ford F150 ?
Transmission down shifts to 3rd gear when I turn on the head lights, and shifts back into 4th when I turn them off?
Not enought facts ,is it 4x4 4x2 what size engine ,does it have any aftermarket assy? does the od drive button flash on the shifter
Repair Help & Product Troubleshooting for 1991 Ford F150
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