The air flow sensor is probably faulty. Quite a common thing with Corsa. The sensor is very easy to change. It is located on the air intake, right after the air filter. Check the part number of the old sensor to be sure you get the correct one. The number might be facing down and should look something like 280 217 123, maybe with a zero in front to make 10 digits.
Corsa owner
May 2009