Hi I've got a 2001 astra 1.7dti. A few months ago i noticed the engine management light beginning to appear. Checked the manual to see what it meant and found that the engine goes into a safe mode for some reason and that performance is impaired and fuel consumption is improved. i've been driving it ever since. it comes on when i start it up. a few minutes later it'll switch off by itself and if im driving on the motorway itll appear again after about 10 miles. However sometimes it doesnt come back on at all. Any ideas of why this could be or if anyones experienced this? Is it a common fault with the diesel versions as a few people i know have got the same problem and it doesnt seem to bother them at all? Is it anything to worry about? Thanks in advance.