how the intercooler is plumbed or where the hoses go wont make it run fast, if its running fast its getting more fuel than it needs as such,
so either you have something holding the throttle open or someone could have played with the smoke screw on the back of the pump which when adjusted in to give more power will also increase the tickover,
however if you have adjusted the correct stop & allowed the throttle arm to rotate back more than what it was & the idle hasnt come down then id say you could possibly have a injection pump issue