Using eTuner Lionheart for the diagnostic... got fault code P0135 - O2 Sensor Heater Circuit Malfunction [Bank 1 Sensor 1] which means the Oxygen Sensor #1 needs replacement.
Local Spare Part Shops and Auta-rized Service Centers quoted between RM800 ($240) to as high as RM1300 ($390) to replace the sensor!
After eBaying for a while I got a reasonable priced original Bosch O2 sensor, $132.98 (cost including express shipping with tracking info) from AutoBody Shop in Latvia.
on the LHS is the faulty sensor
Replacing the sensor is easier than replacing a spark plug on Peugeot 308THP!. Can be done by DIY. Special tool needed is only a 22mm open end spanner/wrench.
Oxygen Sensor #1 location...
Click HERE for myPeugeot 308 other faults and diagnostics