Hey All, I am doing some repairs to the intake manifold of my vehicle. I noticed that the 'idle air control valve' was attached to the manifold with only two screws instead of four. I have owned the vehicle for 8 years and have never taken the valve off before.

1. Is it normal for this valve to be attached with 2 screws instead of 4?
2. Do I need to 'torque' the screws when attaching the idle air control valve?
3. What are the symptoms of this valve not working properly?

Thanks.