You must consult a repair manual specific to your vehicle's year and model. The owner's manual or a shop manual (like a Chilton's or Haynes) will provide the correct torque specifications for your particular intake manifold. Failing to use the correct torque can lead to leaks or damage to the intake manifold or engine.
Trying to find the torque spec online without knowing the exact intake manifold part number is risky. Different manufacturers and even different versions of the same intake will have varying bolt specifications.