Last week my wife and I bought an 2006 Ford Fiesta, within the last few days the speedo started to drop to zero for a short time before coming back to normal - very intermittently.

But today the speedo dropped and a short time later the engine cut out with the ODO showing -----. The tacho, fuel and temp gauges still worked. Once my wife had come to a stop, she turned the ignition off and then the car restarted immediately and drove as if nothing had happened.

When it happened she engaged the clutch turned the ignition off and back on and released the clutch and the engine restarted, but the speedo did not, waited a few seconds, then we drove away as if nothing had happened.

She took the car to Dubbo from Bathurst on Saturday and returned back to Bathurst yesterday no issues but today different story.

I rung Ford and was told it would cost $120 an hour to just look at it. I suspect its something to do with the Speedo Sensor but I could be wrong.

i had issues with my auxr6 auto many years ago

where the spedo would do what you are saying , but no engine issues
and it ended up being the drive gear in the extension housing was stuffed
ohh and then the gear failed and put the car in limp home mode LOL

I have no idea how the fiesta gets it spedo reading whether it is electronic like the b series
or mechanical like AU and before

could be a good place to start?