I posted this question in the old forum but can't remember the answer, so here I go again....
Astra Sport 1999 T, 1.8
Whilst driving around town (and more noticeably on motorways) all of a sudden my engine management light will come on. Approximately 1-2 seconds later my engine coolant light will come on as well. Whilst both of these lights are lit the car is behaving perfectly well. ABout 5-10 seconds later the temperature gauge will drop like a stone down to the bottom of the scale (whilst the lights are still lit).
The gauge will stay at the bottom and the lights lit until such a time as I slow down or accelerate (or so it seems, may be time related?)
The strange thing is that a no time is the driveability of the car affected. The heater still functions correctly and its not consistant. Somedays it's a pain and others it won't do it at all.
I remember the response on the last forum having something to do with a temperature sensor of somekind?