Well actually there is a screw that you can adjust below that vacuum piston which adjusts the butterfly plates in the intake manifold but theres no need to adjust it as from the factory it's set so the butterfly plates open up spot on 90 degrees from the closed position, if you muckaround with it it won't open properly or to it's full degree.
Motor May 2001 Quote: "Believe it or not, there are actually a bunch of weirdos out there who reckon a six cylinder is the dux gutz. Bugger it: I'm one of them" :s5
AUII Late Ed XR6 HP T5 Venom- Full Tickford Body Kit, 17in Wheels, Herrod Bi-plane Spoiler, Momo Steer/Gear, T-Series Interior Options, Premium Stereo and a very light-tuned 4.0L I6
(FPV-Tickford Club of NSW Member and Co-Founding Member of 3FB Inc, Ford Forums Food Bandits)