Does anyone know the correct Spark Plug gaps for the Fiesta ST?
I can't seem to find it in the hand book.

Try the search option it's been discussed before

Then sorry I can't help. Sure it was discussed a few month back tho

According to adam08 the gap is 2 inches. But Dave t st says it's 1.6mm which sounds better.
Tech talk page 9

Cheers mate
looking on Google/Internet it with either 1.6 or 1.3mm I was finding

When using the search function it automatically puts a range in of 1 week you need to remove that

1.3mm is the correct gap mate

Your new plugs should come with the correct gap straight out of the box, if you get standard Nickel Alloy plugs you can get away with adjusting the gap slightly without damaging the central electrode ... just be extremely careful!

If you get Iridium plugs "DO NOT" try to adjust the gap ... you will easily break or damage the central electrode .. just install them and forget them for another 60,000 miles.