02 STi spark plugs
 

Where are they and are they easy to access pls? I don't need to remove just spray with WD40! Cheers

WHY?
Each plug has it's own coil pack on the plug itself which is also bolted to the cam cover. To get to the plugs you need to remove the air filter assembly on one side and the washer bottle on the other. You then need a long plug socket to reach them once the coil packs are removed. If you're going this far you might as well remove them to check and re-gap or replace if they've done much more than 20-25k
As they are, they are in a pretty dirt proof place - they should'nt need WD40 sprayed on them!
JohnD

Cheers JohnD,
I cleaned the engine at the weekend using the D2 (think that's correct) stuff from Halfords and the car has been a bit 'jumpy' first thing - fine when warmed-up though. I thought possibly it was the plugs but I guess not from what you say. The plugs were also replaced approx 7,000 miles ago. I added some Octane boost plus D-Tox fuel system cleaner on Friday which may be causing itb to be a bit more 'jumpy' when cold? From what I read, all STis seem to be a bit hesistant when cold but mine seems more so since the weekend.

Might be worth getting some electrical cleaner ( eg Servisol - NOT WD40) and disconnecting the various electrical plugs - MAF, crank, throttle position sensor etc. and spraying and allowing to dry before re-connecting, just in case some of that engine cleaner went where it should'nt!
JohnD

PS It could be that D-Tox!

Cheers.