I have a misfire on start-up on petrol V6. One of the six cylinders is not firing. There is a 'put put' noise from the dead cylinder.

Driving is a bit lumpy with power dying and surging for the first 5 minutes.

Then after 5 minutes it is fine.

I think the main candidates are:-

Ignition system (leads/plugs/coils)

Oil entering the cylinders through leaky gasket during rest and dripping on the plugs

Water entering the cylinder through leaky coolant gasket

If the problem goes away after 5 minutes does that indicate that one of the above possibilities is more or less likely or are there other candidate issues I am not thinking of?

2001 Manual X-Type 2.1

 

Also for plugs, coils and leads do these need to be Jaguar parts (or non-genuine Jaguar copy parts) or are they generic items?

Thanks