Speedo?? Sometimes It Works Sometimes not so much!!!

[socalocman03]

Hope all have had a great relaxing weekend. You need to be nice and refreshed for your long work week so you can make that money, pay your taxes like good Americans, then watch our government waste it!!!! Yea!!! Makes a man Happy to pay Taxes, Doesn't it?? lol

Anyway, I have a speedo problem, I've read and actually the truck has been in the shop for another unrelated problem at which time they do whatever it is they do to asses the situation with the gauge. However, this is my situation...All works fine for months on end keeps correct MPH, Starts and Stops with the truck etc etc....Then out a the blue it will Peg out completely to the far right (actually puts it at the bottom via a right hand sweep) then drop back to about half way and just sorta float there, start to slowly move back and forth like its doing the wave at a pro ball game and all this regardless of my speed. Then like a light switch is thrown it will start working perfectly again?? WTH??? Either work or don't work ya stupid stupid gauge!!! Sheesh!!! It's a 2006 F-550 Xlt 6.0 Super Duty with just under 50k on the odometer. Not sure what can be done but it really is a PIA not knowing my speed cause I tend to be a bit of a lead foot and it sorta comes in handy, that there speedometer thingy does!!! I'd take it in to Ford but I can't afford to have the truck off the road for a day or two for them to do diagnostics on the truck only to tell me they can't duplicate the problem. Any suggestions would be great.

Les

[blue72]

I had a similar on my 00'. Replaced the speed sensor on the rear axle and no more floating speedo. Hope this is your problem, as it was an easy fix.

[blue72]

By the way, I have also heard the speed sensor is prone to coming loose and getting mucked up. Yours might just need a good cleaning and tightened down?

[socalocman03]

thanks for your reply, I'll need to check the sensor out. Any Ideas as to how one can go about testing the sensor or detect whether it is the culprit causing the problem? Would the sensor work perfectly some days and not work others?

Thanks again for your help

Les