vacuum leak?

[breeze]

When I drive and as the rpms raise I can hear a "hissing sound" as if air is escaping. It sounds as if it's under the hood echoing off the ground when I drive. Vacuum leak or a gasket somewhere?!

[MMBLUE]

If you have headers, it could just be an exhaust connection:dunno:. I got one of those sounds and it's my LTH connection to the straight pipe that makes a hiss sound. I need one of those old skool flare gaskets.

BTW, if it were a vaccuum leak you'd be throwing a code.;)

[breeze]

I wasn't sure. I think that might be the case too. No headers but started when I got my exhaust done or 2nd cat delete, can't remember.