Snail Oto

ok here the proplem ... i have a automatic y8 manifold that use 3 wire iacv but i want to run obd1 so i did the 2 wire fix repin the ecu and change to a ls obd2 TB but i just left the iacv hanging with coolant line run through it the car idle really bad some time 100rpm then it goes up to 1300 rpm it does not bounce but stay thier ... anyone can help ? how do people wit ITB run thier iacv ?