Hi i have a 2002 astra coupe 1.8 it has covered around 107000 miles and recently seems to have lost some power somewhere! when putting your foot down it seems to hesitate through the rev range also when letting off the throttle the response isn't smooth and kinda lurches! the engine management light does come on and my code reader displays fault code p0170 fuel trim bank 1 malfunction. recently the 2nd lamda sensor has been replaced. some people have suggested the air flow meter is at fault however i'm not too sure what the above fault code is all about! all help much appreciated.