got a similar thing with mine, with the iscv connected the revs go up quite high to somethign like 2k and sticks when its cold, not tried it when its warmed up recently as ive kept the ISCV disconnected but could it be the ECT sensor causing that too?! i cleaned it all out ages ago so its not gunked up, car once warmed up for 5mins with the ISCV disconnected runs fine other than a hesitation but thats being put down to the map on the chip on the car being from before the head was ported and needing a re-map!