Sounds like a good one mate.
Usually leads on this model as you may well know.
You've done plugs, leads, DFI module, coil packs.
It wouldn't be the fuel pump as you stated it appears to miss on one cylinder only?
Good idea to check fuel pressure anyway, as the vehicle faults.
Injectors can block up form dirt in the tank but you've stated they've been checked.
A mechanical valve problem would likely be consistant unless a sticking valve is envolved....a comp. test when the vehicle is faulting would rule this one out.
When you say you've changed the module near the end of your post are you referring to the ECU? It is possible the ECU is playing up but bare in mind your engine does not have a cam sensor and therefore doesn't inject sequentially. The ECU controls the injectors in banks of 3.
How long ago did you fit your plug leads?
If it has been a while perhaps it would be wise to carefully inspect the inside of the lead boots for arching marks. The plugs will show signs of this too.
Get back to me.
