Are you talking about the BISS screw? This is what I learned today... on the 1g there's a sort of test port (plug) on the harness up against the firewall by the battery. You make a crimp with about 8 inches of wire and have an alligator style clip on the other end. You plug in the crimp connector to the only pin within the plug, then you ground the other end (alligator clip). That will put the ecu in a sort of limp mode. My friend used a datalogger to test everything and doing any sort of idle adjustments on my car today. Thats how he did it. Too much to explain so I cut it in short... he knows better on how to explain it and do everything. I just watched and learned.