A smaller gap will make the car run a bit richer, 0.035 is ideal for the 2010 stock, but still OK. Nowadays, they put in 0.030 at the factory, maybe tuned to accommodate.
The 44K wont affect the carbon issue because that is on the back of the intake valves where 44K doesn't reach. It could possibly have dissolved more than usual impurities in the fuel system, if they were there to begin with. Shouldn't cause issues with the sensors/cats (permanent). Did you reset the codes and see if they come back?