My truck puts on miles while parked!!!

[hp383]

So I just got a new to me 93 CTD. Its a truck I used to own and was able to repurchase.

It now has an odd condition. While parked, engine running, and at idle, the speedo will read anywhere from 40 to 80mph. The odometer registers miles, as does the trip meter. Again this is while parked, in park.

Any ideas what is causing this. The speedo doesn't work correctly even while driving, the cruise control doesn't work either. It has worked in the past, and worked occasionally recently.

But it is very odd sitting still, and watching the odometer rack up miles! Not to mention hard to tell true mileage, or when to change oil.

Please try to help me out on this.

93 CTD 4x4 3/4 ton auto

[meby]

So I just got a new to me 93 CTD. Its a truck I used to own and was able to repurchase.

It now has an odd condition. While parked, engine running, and at idle, the speedo will read anywhere from 40 to 80mph. The odometer registers miles, as does the trip meter. Again this is while parked, in park.

Any ideas what is causing this. The speedo doesn't work correctly even while driving, the cruise control doesn't work either. It has worked in the past, and worked occasionally recently.

But it is very odd sitting still, and watching the odometer rack up miles! Not to mention hard to tell true mileage, or when to change oil.

Please try to help me out on this.

93 CTD 4x4 3/4 ton auto

Try running down the grounds on the vss. Mine did the same thing only it would hit maybe 20 mph sitting still. On mine it was the connection on the vss itself.