Hello, I hope I can offer you some assistance.
Is this an earlier shape Focus up to 2004.75 or a 2004.75 onwards shape? If you're unsure do you have the VIN? When the odometer stops does it go to dashes? Do the speedometer and rev counter still work?
Let me know and I'll reply as soon as I'm able to.
The VIN number is WFOFXXWPDF4G19975
Model Code 16237
When the odometer stops it does go to dashes but sometimes goes totally blank,the rev counter has never stopped ,and the speedometer always stops working at the same time as the odometer
the temperature gauge and the odometer will be 2 separate concerns.
The cutting out, loss of power and odometer not working will all be related to a vehicle speed sensor fault. This sensor is located on the transmission just above where the right hand driveshaft exits. To replace the sensor requires access to the underneath of the vehicle. disconnect the sensor wiring, remove the small solid roll pin the sensor then pulls up out of the transmission. The roll pin and sensor can be quite tight.
The engine management uses the signal from this sensor for calculations, if the signal is missing it can't calculate correctly which is when the engine loses power or and cuts out at low speed.
An example of the sensor is http://www.ebay.co.uk/itm/FORD-FOCUS-FIESTA-SPEED-SPEEDO-SENSOR-1998-2004-NEW-1087548-98AB9E731AG-/280866641306?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Car+Make%3AFord%7CModel%3AFocus&hash=item4164f4d59a
With regard to the temperature sensor you can check the gauge operation as follows
To enter the instrument cluster self-diagnostic mode simultaneously depress and hold the tripmeter reset button then turn the ignition switch to position II or III.
Release the tripmeter reset button when TEST is displayed on the LCD. This will take between 5 and 8 seconds.
The instrument cluster will enter the gauge sweep test.
To navigate to the following tests while in self diagnostic mode depress the RESET button to move to the next test.
The self-diagnostic mode is deactivated when the ignition is turned to the OFF position.
If the gauge moves when the cluster does the sweep test then you know it's OK, on test 6 the LCD will show dtc, if there is a code d073 or d262 this would confirm the cluster isn't receiving the temperature signal from the sensor. Also if the sensor circuit is open circuit the cooling fan usually runs all the time.
I hope this helps, if I can assist further let me know and I'll reply as soon as I'm able to.