Have you definitely got the correct OFAC map sensor? They're listed on Ebay all the time with an XR2i sensor which won't register any boost.

The XR2i ones are rectangular. A proper OFAC one is sloped on the right hand side.

Will it not rev past 3000RPM when it's out of gear? Or is it only when you are driving it?

What happens when it won't go past 3000?