That doesn't have anything to do with the car misfiring. All the heater circuit does is warm up the O2 sensor a little faster so that it can start working a little faster. If the O2 where not working or if it where stuck lean or rich there would be a code specifically for those. If those codes where present I would say your on to something by suspecting the O2 sensor.

To find a misfire you can pull off plug wires individually and see if the RPM changes, Check the spark plug condition, Check for good spark at each plug, wet down the ignition wires with the engine running and see if they leak spark, etc.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

P0030....HO2S Heater Control Circuit (Bank 1 Sensor 1) and to be truthfull i havent a clue as to what its refering too , i can only sumise its something to do with the heat going into the inlet manifold from the cooling system and a sensor is reading the temperature and adjusting the fuel mixture accordingly .sorry i havent been much help for this but if you ever change a front wheel bearing then make sure the grey coloured paint is fitted to the sensor side (interior by drive shaft) or the ABS light doesnt go out