I have a 2001 Legacy GT 2.0 with code 45 pressure sensor, I suspect this is the MAP sensor; is it? Is there a test for this sensor, how is it carried out? this vehicle idles like crap when it's cold and as it gets warm it is much improved; any GURUS out there want to advise on this one? Vin # BH5-142519 Eng# B3230864.