just changed:-

Oil and filter
new plugs
fuel filter

and added some Wurth fuel additive

went round the block and all of a sudden the CEL light came on and the throttle at stand still was going up and down itself between 1500 - 2000 rpm.

drove home slowly stopped and the CEL went out so i thought right, and took for a slow spin again and everything was fine.

any ideas ???

p.s - i overfilled the engine oil abit could it be because of this ? im going to empty some out tomorrow.