exhaust leak? u mean neutral as in the car is stopped completely and in neutral? i have an automatic im not familiar with honda manuals yet i can drive a manual. just never drove a honda one. u could have an exhaust problem or possibly a clutch problem. drivetrain issues would go away for the most part in neutral. axles, wheel bearings r movement oriented. stuck throwout bearing not releasing the clutch completely. check the exhuast completely from the exhaust manifold to the tail pipe. u could have lost an exhaust hanger and the exhaust is hitting the underside of the car. a heat shield could be bad.