Can anyone help?

My frst wont run at all with the map sensor disconnected.

If you disconnect the vacume pipe into the map sensor and leave it with air leak the car will drive fine and idle fine apart from it will misfire on boost.

If you connect the vacume pipe into the map sensor it wont idle and judders when you first pull away but feels great when on boost.

HELP!!! Is this a fueling issue? If so what do I do?

Cheers.