My March 89 740 turbo auto with 160K has been cutting out intermittently when driving for some time. Generally within the first 5 miles although sometimes further, worse in hot weather, speed irrelevant, restarts after 5 to 20 minutes. The temperature gauge never goes beyond mid-point (1200 position) and when overheating it flickers before zeroing. The dying seems connected to the gauge playing up - but the car cannot have overheated half a mile into a trip from cold. Just had a new turbo valve bypass hose and engine coolant temperature sensor. Today it faltered after 3 miles but recovered when I shifted the transmission into first. The revs don't zero. Later it stalled twice when driving slowly across a field. Where do we go from here? Fuel pump relay? Any other relay or sensor? Could the auto box be the problem? My mechanic is a saint but we're losing sleep over this one!