Changing plugs is pretty easy on this vehicle.
First you will need to remove the ignition coil cover plate by removing the two screws holding it on and lifting the cover off.
Underneath you will find four ignition coils, each held on with a single 10mm bolt.
Remove the 10mm bolts, unplug the coil connectors and remove all four ignition coils.
See illustration for clarification and torque values for reassembly:
Once the four coils are out, you can remove the four spark plugs. Use a 5/8" spark plug socket and a 6" extension and ratchet.
For installation, you need to use either NGK FR6EI or DENSO K20PSR-B8 spark plugs and DO NOT adjust the gap; they are preset from the factory and attempt to adjust the gap will damage the electrode tips. Torque to 18-19 ft/lbs.
See table below for factory recommendations:
Use the torque specifications found in the first picture for reinstalling the coils and cover once the plugs are changed.
Some DE base model Lancers will not have the cover over the coils, if this is the case for your vehicle, simply skip this step and go right to the coils :)
If you have any problems let me know!
Edited by Doug C on 2/4/2010 at 8:03 PM EST