Your saying that your shop manual says torque them down in 2 steps correct?
Not This Method
1. Torque to 28-31 lb/ft
2. Tighten an additional 90 degrees
3. Back off bolt one turn
4. Torque to 28-31 lb/ft
5. Tighten an additional 90 degrees ( I'm wondering what the torque value is about now)
6. Tighten an additional 90 degress ( I know I'm gritting my teeth as I'm expecting the bolt to break off in the damn block)
I'm saying that I followed the above procedure exactly. I've also said,......I have a 2 valve 4.6 in the car.