Help needed with this one please, becomming a real pain.
Vectra Z18XE poor performance, especially from cold, though not much better when warm.
Has erratic idle, and is running very lean.
Front O2 is stuck at 20mv, occasionally dropping to 0mv, and occasionally 39mv. If you jab the throttle it reads around 750mv for a split second, of if you spray carb cleaner in the intake it does the same, hence i dont thing the sensor is faulty, more it is giving a true lean reading!
Vehicle has had a new airflow sensor, and a replacement ecu has been tried but still the same.
No air leaks apparent at all.
Only fault codes are for Lean exhaust, and incorrect o2 switching.
Any help or experience greatly appreciated.