2006 f250 6.0 78,000 miles. , edge evolution, aem air intake. i have been having problems wiht the speed omiter. can be driving and it reading way above what i am doing. (driving 60 and reading 90 or worse.) came home on the interstate doing 70 and it was almost back to 0. it happened a month or so ago and then did fine for a while. have not checked for codes. will do so with the edge and a code reader. not sure where to start looking.

 

Sounds liek your Speed Sensor is going out. The guage will bounce around or completely shut off. Happened to me last year. The sensor is located on your rear axle housing. Just unplug the wire. Unbolt the ( i think 10m bolt) and pop it out and replace. The sensor runs about $95 at Ford.

 

Try cleaning it first, real easy. If the clean doesn't fix it, then get a new one. Right on top of the rear pumpkin. I believe they're magnetic so they pick up all the files and shavings from the rear end, then stick to the sensor. Just clean it off first and try that. Real common with these.

 

thanks for the help. will try to clean it when it warms up today.