Quick Engine Problem

Pug 306 petrol:

a friend says:

"Oh and any other suggestions for what might be
> causing a cylinder not to fire? (new spark plug is wet and black, as
> was the old one)..."

any ideas amongst the

its had a new coil pack, air filter, fuel filter and cleaned idle control valve

keeps stuttering and one cylinder will not fire - dead injector? lambda problem?

thanks!

Tim