BMW: eratic idle, air flow meter, vacuum hose

Question
Hello,

I have a 1990 525i.  For the last couple of weeks when I start my car the check engine light appears which is then followed by erratic idling.  A mechanic looked at it for 15 minuets and told me that it was a loose vacuum hose.  The mechanic put a clamp on the vacuum hose and erased the fault code.  I am still having the same problems and my light is still appearing.  What do you think?  

Answer
Nick,
 I would have the fault code read, and find out exactly what the car is saying?  When the check engine light comes on, it's because the computer found a problem with one of the sensors.  Your car is an earlier one, so there will only be a few fault codes to show, bust never the less I would have it checked.  

 There are too many possibilities for me to narrow it down to one cure, so I'll recommend having the code read by another mechanic, and take note of what the code says (i.e. O2 Sensor, Air flow meter, Idle control valve...).

 Good luck,
 Josh