06 WQ speedo drops to zero intermittently

[pal65]

I purchased my 1.6 LX manual fiesta new in April 06. It is a great car and is driven daily (170,000km) all freeway driving.
A few months ago the speedo started to drop to zero for a short time before coming back to normal - very intermittently. About a month ago 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 I had come to a stop, I turned the ignition off and then the car restarted immediately and drove as if nothing had happened. Once when it happened I engaged the clutch turned the ignition off and back on and released the clutch and the engine restarted, but the speedo did not, I pulled over, completely stopped shut the car down and restarted and drove away as if nothing had happened. The problem may occur once a day for 2 or 3 days and then will go away for maybe a week.
I have rung Ford and been told that they have never heard of it, bring it in and we will run some tests! That sort of response generally comes with a hefty price tag.
Is there anyone out there who may be able to shed some light on this problem?

[Billy99]

Sounds like a computer glitch of some sort.
Might make a suggestion, may or may not work, worth a try. Erase the ECU memory.
Firstly, make sure you have the radio pin code. You will need this afterwards to activate the radio. (If you don't have, can be obtained from local Ford Dealer with VIN and proof of ownership; rego papers are good)
Disconnect the negative, and then postive leads from the battery.
Connect the two battery leads together and hold for 30 seconds.
Reconnect the positive lead to the battery, then the negative lead.
The engine management will reload default values back in memory.
Trip meter will be reset to zero and radio code will need to be re-entered.
Regards