I can remove the spark plug leads from cylinders 3 & 4 with no effect to a rough running engine, any ideas, i've tried new plugs, lead, coil pack EDIS module, swapping leads over on the coil pack but nothing works.

i need a quick answer in a major bother with it now

Have you got fuel getting into those cylinders can you smell petrol, are the plugs wet when you remove them. Have you got compression perhaps a valve is sticking

Do a compression test, May have done the head gasket across 2 cylinders.
May be valves but its a bit suspicious that its adjacent cylinders. Also check for manifold air leaks.
Steve.

are the plugs sparking - hold the plug to the engine bloke (using insulated pliers). You should be able to see / hear the spark.

be careful if you've got petrol and air around

what carbs are you running?? Sounds suspiciously like you arent getting any fuel in there to me. Could be the float sticking and not letting fuel in if you are using webers - pretty quick to check anyway.

just to up date this i have changed nearly all parts, fuel is getting in plugs look like it is rich.

i have now found the problem i'm running throttlebodies and cylinders 3 and 4 were tight shut at idle, causing me the biggest headache,

Thanks for all the thoughts on this