Why are my plugs all different colours?

[pete]

No o2 sensors.

Its not burning oil. Level hasnt changed.

I did find a nick in one of the wires to a coil today. The wire was exposed and rubbing on the flapper valve vacuum actuator under the airbox. But the actuator isnt earthed to anything. It was rubbing on the wire for the 2nd plug from the right.

that wouldnt affect all 4 cylinders, only the cylinder affecting the coil,
but as u said, if its not earthing on anything, or the wires arent broken
then ull be sweet.
id be getting it tuned properly and going from there,
otherwise u could be just chasing ur tail.
from what ive read on here, they come out rich from the factory
to start with.