I hav a opel corsa 1998 160 is sport. Car starts idles a bit and then cuts out. What can the problem be?

check wether its spark or fuel and check the fault codes

We do not have Opel brand here.

I would think there is a sensor issue, possibly temperature related. Fast idle is usually when cold or the battery is low.

Is it getting red hot at the exhaust manifold? Or at the exhaust tip?

follow the wire's back from the bulb holder , the earth wire will be the one that is bolted to the car body/chassis , earth wire's are usually black

This car is a one point injection motor.So there is a screw
to adjust the revolutions. If you cant find it ask a mechanical
to show you,

change spark plugs

A similar thing happend to me turns out it was the idle rev cold switch thing>
basically the switch which provides more fuel and revs when the car is cold, so that when you start the car it doesnt just die off.
the switch itself is a bit mechanical and is perhaps jammed on the full on position. If it happens more when the car heats up. then it is this switch.

what you can do is start your car one cold morning and see how high the revs are, if its still high then its probablly not the switch

should be ok because a thing called a zena diode in the alternator should have protected the alternator