[Rev]

When I torque intake bolts, I do it in stages (same with head bolts). I do it in the recommended sequence in 3 stages. Like 10 lb/ft, then 20 , then 30 all over again for each sequence. After the last series, I go over the whole sequence again to the recommended torque (maybe slightly more but not much).

That allows the manifold (or head) to seat down evenly over an extended series of torqueings. I believe this helps the loosening problem.

Rev