So if you clear codes then restart vehicle is it instantly misfiring.

If not, then if you use the noid light on the next startup does the noid light flash as it should.

Doesn't take long for the misfire count to build up then the ecu will shut down the cylinder specific injector.

If compression is equal and good (i had a polo in with just over a bar difference that misfired due to valve issues) then i'd suspect an injector if ignition coils have been swapped about.

thanks
lee