Originally posted by zaphod_fl:
It was somewhere near the "A", which is okay for a Zetec. Looked down sometime later and it was all the way over like the engine was cold soaked! As I picked up speed past the accident, it jumped up a little, and by the time I got to work (say 15 min) it was back where it should be.




I had the same thing last year, from time to time it fell to
zero and gradually went back up.

To verify, when it is down, stop the car, (leave the engine
running), open hood & tap the thermostat housing and the
wires. For me it looked very much like a wire contact
problem (moving the wires always / tapping always solved it
momentarily) but at the end it turned out to be a sensor.
It was < $20 from autozone, and it was the one facing DOWNWARDS
from the thermostat house.
Both autozone & dealer kept saying that the gauge is driven
from the other sensor (facing upwards from the th. housing),
I changed it for no result, finally changed the
other one and it fixed the problem.

Tiv