Last month I had my 04 Volvo V40 in the shop to have the rough idle checked out. I have already replaced the usual suspects on this car: IAC, plugs, fuel pressure regulator, thermostat, water temperature sensor, cleaned the throttle body and Mass air flow sensor. The shop advised me that I had a code indicating low boost pressure sensor, and that the best way to resolve that was to change both the barometric pressure sensor and the boost pressure sensor at the same time. I was also recommended to change the coils and wires as those had not been done yet. After this I am still getting a rough idle first start of the day. As I always do I ordered the OE parts from IPD and they came up with two sensors required.

The problem is I have found the Boost Pressure sensor and the manifold absolute pressure sensor (same part number) I have not been able to locate the barometric pressure sensor (different P/N than the other two).

From what I have found and been told it should be located on the center of fire wall under the black cover called the relay panel. I can not find anything back there that looks anything close to a pressure sensor.

1.Can some one with a similar car possible get a picture of where this barometric pressure sensor is?
2.Should I also change the manifold pressure sensor as well?
3.Where should I go next on the rough idle?