My idle is playing up. Can't get it right.

If I stop at the light, then it's always fluctuating (spelling???) between 750 and about 1500rpm.
If I just stop and let her run for a few minutes, then it settles at about 1100rpm.

The idle speed valve has been cleaned a few days ago so that can't be it.

Think a new valve is on the cards. Anyone got any?
Perhaps a FINIS code to see if Ford still has these?