1st I would do is check all the plugs. If misfiring they will look different, alot can be told of a engine by looking at the plugs.
Then switch coil pack and wires from 1 2 and 3 with the misfiring 4 5 and 6.
Either pin point or rule out before throwing parts at it.
Run some good injector cleaner.
Do you have a laser temp gun?
After warmed up checking Temps from each cylinder and comparing, can tell if acouple cylinders are running lean / rich.
Mechanics stethoscope is good to listen to injectors and valvetrain while leaving covers on.
But if it runs good and never noticed a hesitation a sensor.