Okay folks...quick setup here...ive got alcatek ecu with wideband sensor and oe narrowband in mid section of exhaust. When running idle and shes running nicely the wideband reads nicely but narrowband says lean. Ive got one of those led displays for the narrow and its quite lean but you can tell the car is happy. Then randomly she ll go rich and rev by which the narrowband reads okay but wideband says rich...im thinking its possibly when the closed loop idle kicks in. Whats easiest way to confirm which sensors are 100% correct, so i can replace the duff one? Exhaust gas analyser?

 

If anyone has oe rear 02 sensor for sale...pm me please

 

A mapper or mot tester would need to confirm which one is correct.

 

Good point...might have word with bob