hi guys i was driving wifes 147 today and after refiling petrol here it came the ******* engine management light p 0141 bank 1 sensor 2 heater and this after i replaced 2 exhaust valves and all front suspension .now i ve deleted and comes every second start so i cleaned al 3 lambda conectors and all relays in the engine bay no luck thougt.wich one by the way is bank 1 sensor 2? 2 in the manifold left right looking at the engine and the lower under car one? this came just after i pour some petrol in and start it again so out of the blue .any other causes? sugestions? thanks in advance.