You can get the replacment clip seperate from the entire inlet manifold, dont let Ford try and flog you £600 of inlet manifold as you just need the clip if it is indeed broken.
A busted control unit can give itself away by clicking like mad when the ignition is turned on. If you remove you air box i makes it easier to see the DIS clip. If it looks intact then get a friend to turn on the ignition and watch the Clip, if the control unit if functioning correctly as soon as the ignition is tuned on it will pull the arm back and hold it there, then when the revs get up past 5000rpm it resets back to the original position to switch to the shorter runner. Obviously no need to rev it up you just need to see if its working.
Also try to gently move the flap with you hand, you will feel the flaps move inside the inlet manifold, there should be no sticking and it should be free to move, maybe yours is getting stuck.
ST170's eh, when they go wrong they go really wrong, i got the clutch and flywheel to replace on mine!! which is £1200 fitted haha...................eek
Last edited by Sp3no; 08-05-2009 at 03:42 PM.