I have faced too, like many others, the ignition coil.
The SYMPTOMS were:
MISSFIRE, LUMPY ON IDLING , POOR PULLING POWER, VERY POOR FUEL ECONOMY, POOR STARTING, NON RESPONSIVE ON THROTTLE, CUTTING OUT ON IDLE.
The screen showed injection problem, the check engine light turned on and the computer diagnosis showed No4 cylinder.
I replaced it with a new "sagem" coil.
When I unscrewed it, I found plenty of water in the hole which means that the owner before me (or the seller) washed the engine to make it shine.
So be careful and avoid using water under the hood.
This cost me 65 Euros (about 55 pounds).
To tell the truth this malfunction scared me a little bit because in 9 years with my ext Mitsubishi Lancer and with more than 160.000 km with it, I had never faced any problems.
So I ordered http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=120475722167. I have not installed them yet, but i have them stored in the trunk for any case.
