Trying to make final adjustments to my 89 notch mods in signature. Pulled all codes and got code 11. I know the base idle is off because before when I was having problems I made adjustments to the idle screw. I read through the idle surge checklist and was attempting to reset the base idle. When I unplugged the IAC and had the spout disconnected the car surges from about 650-1000 rpms. I know all sensors check out, no vaccum leaks found, base timing is 12 degrees. TPS is set at .98. I cleaned the IAC. With the IAC hooked up it idles at 950-1000 rpm with no surge.