kenk

I have a 2007 f150 that's having some speedo issues. About a year ago it started acting up and found it was the abs wheel speed sensor. I replaced that, and it worked fine for a long while. Well it started doing it again. I had my rear diff serviced and then replaced the sensor again. Well its not working now. It reads a much greater speed then Im going, and itll actually stick when the trucks in park from 10 to 110 mph. Im a handy guy, but don't know a lot about this stuff. Im thinking a wiring issue or gauge cluster has gone to hell, or possibly another sensor somewhere? Any help and insight would be much appreciated. Thanks Ken K