I have 91 with 73xxx miles with apx turbo kit running 7 psi. The car runs perfectly normal, smooth idle and everything, no burn oil, no smoke, check catch can don't see any sign neither. Two days ago I noticed the car only pull -10 at idle it seems too low for nsx motor, highest is -13 then goes back to -10. I'm gonna do leak down test when I have time. Any idea what wrong with it? Burn valve? Worn piston ring? Vaccuum leak? Thanks