Rough or refusal to run

[Wilsonsp2]

Returning home from Scotland on the normal reliable R1200S, it first started running roughly and would only idle at about 2500rpm - awkward for riding thro Glasgow on a Saturday! It calmed down over my lunch but by the time I reached Gretna Green it wouldn’t idle at all, and stalled whenever it could. As I reached home (Preston), it was back to idling at 3500rpm. I’ve now got a Fault Code reading of 271a Oxygen Sensor. Any thoughts or experience, please - otherwise it’s a skip.

[dobbo]

Could it be an air leak on the intake side? Check the caps covering the vacuum gauge connection, rubber manifolds etc.

[slparry]

or even a duff lambda sensor, I had one on my F800GS once and it was a pita at low speed running. Plugged the GS911 in and the output from it was jumping all over the place so no wonder the ECU was getting confused

[Humbug]

Possibly a coil? mine would cut out any opportunity until I found one of the coils duff. Just pulled them off one at a time and listened for any change in engine note. It was a bit erratic as to when it would cut out, maybe temperature?