Speedometer Reading all over the place

I have 2007 Columbia my odometer keeps fluctuating when driving and my power cuts out as well . I noticed when parked my odometer keeps moving and my idle doesn't work and the mileage will not stop counting....any suggestions please help

 

Similar issue here, Kenworth T680 Paccar MX13- recently experienced erratic gauge behavior. Our cruise fault goes off, ABS light triggers, lose traction control and speedometer downgrades dramatically. It also affects our ELD. Thinking it is wiring harness but not sure. Shop told us it is the ELD which is not true due to our own troubleshooting it with a completely different ELD system we never had problems with. Switched it out and same issue. Biggest clue is it ONLY happens when it rains a good amount and then the truck freaks out. All dash gauges go crazy, same fault lights trigger and then comes the speedometer power loss. Any ideas or input would be appreciated.

 

Usually corroded or rubbing wire for a wheel speed sensor that gets path to ground when wet . The wheel speed fault will be best starting point. Most I found are under greasy 5th wheel area!

 

I'm having same issue speedo reading erratic but no where near the actual speed of which the truck is moving Ive replaced the speed sensor and the speed gauge itself in the dash gonna be checking out the abs wheel speed sensors.... Although I don't have any abs or traction loss issues from the dash

 

Carry a stopwatch, mark the time between mile markers and your RPM for a given gear.

Until you can get it fixed.

 

I have a GPS with satellite speed I've been using that..... But it's really annoying driving with the speedo all over the place and also with no cruise control

 

I can accept that.

At least until the wonders of technology reaches into a person and fines them for thought crimes in the future. I recall a Stallone film that had visited that possibility once or twice and was fined.

 

Just had my speed sensor replaced yesterday and today speedometer going wacky again could it be they didn't clean the housing before they installed the new one, or could it be the harness

 

How did you actually find the "Middle of those 2 wires without either scrunching yourself between the steering arm/frame and rear of motor/ or removing complete fender well Is your ECM tucked up right where the Frame is making it a ##### to get to?

 

My tranny has two sensors
Should I just replace both
Each has a different style plug