I just installed MAFT Pro running speed density. MAP is reading 89.5 with key on and 15-17 at idle. I was expecting 100 with key on and 30-50 at idle. I've tried multiple vac sources with the same results. Boost guage reads 20-21 in Hg at idle so I'm pulling good vac. My question is are readings this low abnormal meaning I have a bad sensor or other problem? Thanks