Although its very easy, since i took afew pics i thought i'd post a quick guide of how to change the sparkplugs in a VX.
I came to change mine last week and i didn't have a clue where to start (never done it before on any car

First i realised that the spark plug socket that i already had was miles too big so i went down to Halfrauds to pick up a new one:
The one i used was 16mm Deep x 10mm:

Now, onto accessing the plugs, just remove the screws from the top of the coil pack:

Then lift the whole coil pack out, i didnt disconnect it, i just rested it in the engine bay:

Then using the spark plug socket and the ratchet spanner, remove the spark plugs. Mine were very hard to remove, especially the far right one that showed signs of water ingress.

Here is my old plug next to the new one (i used genuine GM ones and they were approx £17.00)

Then simply do the reverse,

Job Done
