Alfa Romeo Repair: Spider not performing, air flow sensor, poor reference

Question
Hi stephen, i have a 1996 2.0 tspark spider which doesn't seem as lively as it should be. I got my mechanic to scan the computer as the eng mgt light was on, he said that there were 2 fault codes 07 air flow sensor and 08 phase sensor, he said that the car wouldn't start if the phase sensor wasn't working and that a new AFM would probably clear both codes.i replaced the AFM and when i took it to get the codes cleared the reving was all over the place and it seemed like it was flooding the engine and there was a strong smell of petrol, the mechanic was baffled. on my way home the car wouldn't go over4000rpm or 90mph. thanks in advance
Paul

Answer
If I saw those two codes I would suspect a bad plug connection or a poor reference voltage signal to the units mentioned in the codes. I would not change them without testing with either a DMM or a DSO.  The code scanner is only a start and too often is used as a crutch and an excuse to look no further.