=)What shod it be at idle?
- In vacuum. This depends on the gauge. I believe mine reads positive pressure in psi, and negative in inHg. I believe it sits around -20. Regardless, should be under zero.
- Whatever your target boost is. This will depend on RPM & Load, and more so your specific car. Stock 08+ I'd expect 14-16psi. I'd be concerned that you have a leak if its under 14 psi at peak torque (3-4k RPM WOT)
And during normal driving?
- Somewhere between idle and zero normally. It tends to "center weight" at zero on my gauge due to the change in labels (psi from inHG)