or jack stands and check to make sure nothing is touching the exhaust (plastic bag, animal, garbage, etc). Followed by dropping your exhaust after the downpipes, shine a light down there and check it out.
1993 Nissan 300ZX Slicktop (Oxford Gray Metallic) 1992 Nissan Skyline GT-R (Gunmetal Gray) - Long Live the Z and Godzirra! - "Love cars. Love people. Love life." - Mr. K.