Savannah Buzz…my speedometer was going nuts the other day & kept dropping to zero while the prob was happening with the loss of power etc. That was a lot of info & you may have went over my blonde head with some of it lol. But I'm determined I'm gonna learn all about this stuff.…

 

The Vehicle Speed sensor tells the ECU how fast you are going. This is done with a small module in the dash cluster and the sensor which is back on the transfer case. In the event the Rover approaches take off velocity, around 114 mph, the ECU begins to cut back on fuel and spark to slow the truck down and protect the idiots inside from their own foolishness.

The VSS can fail and do this at normal roadway speeds. You can unplug the sensor and drive to see if problem goes away, speedometer won't work and cruise won't work. The sensor is fairly expensive, over $100. There is a rebuild article in our tech area. Yes, you can operate a vehicle without a speedometer, and use your GPS for speed ove ground.