Re: the high idle or idle hunting....
Do some research on the
PCV valve for your car - like in UK forums for example (Mk6 or Mk6.5 Fiesta). On some motors a cracked hose between the
PCV valve and the Intake runner can leak extra air into the intake and cause idle problems. It is a thing on many cars. It definitely affects the XR4 and is a right ***** to access on that motor, but it has also happened on my BA XR8, which was much easier to get to.
Luke