xssive

iTrader: (123)

Cruising at highway speeds, if I tap the throttle, I get a weird noise that sounds like an exhaust leak? Is this a blown header gasket? I dont see any traces of exhaust leaks on the top side of the header atleast...


I cant hear it at idle


Any ideas what the noise could be?

xssive

iTrader: (123)

EGR and Air have been off the car for years. This sounds like a loud hissing sound when I give it a quick blip of the throttle while cruising.

oword57

possibly just excess fuel detonating in ur exhaust pipes

Smoke_Ford

Maybe a bent pushrod. The tapping from bent pushrods and exhaust leaks are commonly mistakne for each other. Plus, I know on 98 and 99 F-cars there was a service bullitin for pushrod bending on M6 cars. I know this because I work at a Chevy dealership..

DaddySS

I would think that a header leak would be more obvious under acceleration and would sound more like individual popping or cracking sound than a hiss. At highway speed, a hiss may be an intake leak. Check all you hoses, clamps, etc. around the intake area. Open the hood, raise the RPM by hand and blip the throttle from there, you'll probably get a much better idea.