got a problem with my Seat Leon Cupra R ( 210bhp AMK engine)

basically the engine management light is on, i've had the faults read, and they say;

ignition - open circuit cylinder 2 and 3.

Now i've changed all four coilpacks (non-genuine) and the fault is still there...

The car drives perfectly, doesn't missfire and still pulls as it should!

but it was supposed to be sold yesterday, understandably the buyer was put off by the light!

Does anyone know what the problem is??