The engine fault light recently came on at the.

The engine fault light recently came on at the same time the car started running with flat spots and reduced power. I put the car into the garage for diagnosis of the fault light fault, and was told the coil pack was at fault. I replaced the coil pack and although the car ran well, it would not idle and cut out. I replaced the idle control valve but the car still will not idle and have now altered the throttle stop to enable the car to idle when stationary for the mean time until a cure is found. Hope you can assist in my dilema.