That would have been my post.
Mine idled bad always. If its on cold only then I'd imagine its a dirty throttle body, or a dirty isv. Both very easy to clean and both will make a big difference.
However it is good to clean the earths every so often, keeps electricity flowing.
Obviously the battery terminals, then an earth from the coilpack to the cylinder head, one at gearbox, a positive at the starter motor and that the ones I can think of. I may have missed out one or two. Just follow the battery cables.
Remember to put them back on afterwards, otherwise you could fry the ecu or other stuff.
