ok where to start. i recently put on a 68mm tb on my EF XR6 and since then my idle has been way too high, ive done numerous searches on this and i tried everything that i found and nothing is working, i have tried setting the idle without the isc connected then disconnecting the battery, waiting a bit then connecting it all back up but this didnt work, ive tried making my own gasket for the isc with the holes about 4mm wide but this also doesnt work, i have even tried driving it with the isc disconnected but still nothing. when i start the car the revs are about 900RPM and after a drive the revs go up to 1500RPM with the car in neutral.
any help on this would be great because it is really pissing me off big time
cheers

have you tried blocking off the isc completely with a gasket (no holes), then turning the throttle body screw all the way donw, then adjusting from there

simply disconnecting the isc still leaves the air to bypass

I would guess a vacuum hose off somewhere?

first try adjusting the idle speed screw so the butterfly is completely closed...

if it still revs too high you may have to modify your TPS, drill out the 2 screw holes to a bigger diametre and slightly rotate the tps till the car runs well (from memory is has to be rotated anticlockwise). the angle of the butterfly has probably changed a little, some cars seem to be fussy, and some cars it doesnt even bother....

i did about 30 of these units last year, 2 people had problems, 1 was a manual EF and the other was an auto EF, about 25 of them were fitted to EF/EL (mixture of auto, manual, modded, non-modded) and had no dramas with them....

ill try to block it off completely and fixing up the tps position
im 99% sure that there arent any vaccum leaks but i will double check that
thanks

I had this problem after I fitted a big TB. I made a gasket with 4mm holes and tha tmade the revs better, but still too high, especially after a drive. Then I discovered by accident that I had a vacuum leak at the MAP sensor. Plugged the pipe in properly and the revs went back down to normal. Revs still fluctuate a bit on my car, but I will fix that now that I have finally discovered the above post by FAST-XR; prior to this I had no idea how to adjust the TPS in order to correct idle.

Thanks!