Sorry for the bad news but this is common enough that the factory released a Technical Service Bulletin on it. I have included it here.
FOR VEHICLES WITH RUNS ROUGH/MISFIRE
Should I get the work done by private garage, it will be cheaper than dealer. Are some fit to do it?
Previously to this engine trouble, we had numerous faulty ignition coils at 42k miles replaced under recall. Will they have contributed to this lousy engine?