[pyrohamish]

What does the switch at 1 do?
Should the wire at 2 be connected at 3? looks like its been disconnected for ages, but yesterday the engine started running really rough and seem to be misfiring?
Could the engine be running rough from a fucked water pump/valve thing that opens at correct engine temperature that I cant remember the name of?

[suzibob]

Yes the wire should be connected to that engine loom. As much as I no it's apart of the egr setup and used to "bring down the idle slowly" when you come off throttle. Some carbys have a vac operated valve instead.

And you talking about the choke. Usually the wax pallet wears out and you need to replace it. Or tie it up so it's always open. Also check to see if your spring is operating the way it should