Boxster 2.5l MOT Fail Lamber Sensor
 

I have had my car back after petrol treatment added, then new clamps on cat and exhaust du to poor fit, and it is still at best 1.05 on airflow Mixture. Had car tested and all the lamber sensors was OK no faults read?

Any assistance appreciated.

Regards
Mike

When the faults were read, was the diagnostic computer specialized to the Porsche brand? PST2/PIWIS/Durametric?

The lambda sensors (O2 sensors) on UK cars can be different from the US versions. Is yours the one sensor per side version?

How many miles? Any mods? Any work done recently?

Petrol (gas) treatments take a tank before they have much effect.