hello!! i have a 1992 Supra Turbo Auto. the only mods are K&N intake, ZW motorsports downpipe with divorced wastegate, and a custom 3" exhaust. whenever it's hot outside, and only when it's hot there is a nasty noise right below the trans. it sound like pressure is coming out there. I know it's not the ddp sound. more like pfffff pfff fpffffffff. mostly while i give it some gas, and sometime at idle. The muflfer shop cant find any leaks. U guys think it's the downpipe that's making that noise?????? any advice on what i can do would help. Thanks!