i have been doing alot of work on a mates cdti 1.9 (8v) vectra and it has now started surging under power and then going really flat and sluggish. it causes the EML to flash on then go back out and the car then runs normal for a day then does this all over again
upon scanning the ecu, i get two codes, one for vehicle speed sensor fault and a number of pending codes for air flow sensor.

has anyone had this fault and nailed it down?

thanks