Help Needed Tachometer?

[tatt4u]

I have a 2006 f250 6.0 and for some reason the tach gauge will not read right some times. The first time was about 7 months ago right before my oil cooler went south on me so I assumed it was related some how. I got all of the work done and it didn't do it again until last night. Going down the highway at 75 and its reading 1000 and slowly dropping even as I maintained speed. I could accelerate and it would move up but not to where it should be. After I exited and stopped at the first light it fixed it self?!?!?!?!WTF Is this a symptom of a bigger issue, or just a bad cluster/sensor ?

 

[RandyH]

Possible it might be a stepper motor (meter movement). Not sure if the Superdutys use the same stepper but there is a group of passenger cars in that same time frame that have a well known issue with failing stepper motors in the clusters. I just replaced seven of them in my wife's '05 Mustang GT a couple of months ago. The gauges would intermittently or permanently read way off scale or just drift out of position. Our Mustang had 3 that died before I replaced them all. You might search the web for similar issues with the Superduty cluster. I did see someone offering repair services due to bad steppers. Hope this helps. Good luck.