147 Lambda Sensor Diagnostic Result
I have a 147 1.6 lusso 2004 that has been experiencing poor fuel consumption. After getting it checked out mechanically, there is nothing wrong with it. I had a diagnostic check run a few days ago and no codes for faults appeared and most of the sensors appeared to be operating fine, including the MAF. However the graph chart for the before cat O2 (lambda) sensor, despite not being erratic, was a constant moving line from very high to very low, even when the car was in idle. This is in comparison to the post cat lambda sensor reading which was a constant horizontal line when in idle.
Does anybody know if this reading shows the pre cat lambda sensor to be faulty?
What should the reading be like?
If I do need this part, where is the best place to get it from?
Thanks in advance