895.8

I have a 89 with a 5.8 and true dual not cats with 40 series flowmasters on my truck. And I can't hear it. When I press the gas I get a noise from the engine like air it's not a vacuum leak truck runs great I'm guessing cause its an older engine but I dunno any ideas.

mr7confused

Like it isn't loud? And you hear air under the hood? Is your engine pumping backwards? Hahaha kidding.
Air like a forced sucking sound, possibly EGR?
How's your air filter?

FireRescue4465

you probably have a manifold leak...i have the 351 5.8l and i have a manifold leak and it sounds like air coming out of the engine...i also have a flowmaster but i left the cat on it...i can hear it but its not as loud as i would like it

cgossett

How are your ears?

895.8

Well I think my ears are find wife would disagree but o well. When your stopped at a red light next to a semi and he starts to go and you hear air blowing as he takes from the engine bout the best way I can describe it.

895.8

It's fine when I'm idling but when I give it gas it just air I cant tell if it's sucking in or blowing out but it's loud and I don't believe it's a vacuum leak or if it is I've never had 1 that sounded like this

farmer12

Can't hear it With the hood up revving it a lil? Have you done anything to yer intake?

Im runnin a vortech 40 style muffler an they're way louder than the flowmaster 40s I have on my 97 351. If yer tips go straight out the back thats bout how it'll be...I used to have mine out the sides behind the tire an I could hear it...but rocks just destroy the tips.

895.8

I have them comin out the side. And I haven't done anything to the intake. And I have rev it up with the hood up but I can't tell I'm no mechanic

mud-digger

I had my first truck full open exhaust, like manifolds to gutted cat and that's it cut off right behind the cat. And had no sound. R u sure your not hearing your fan blowing air.

895.8

I'm thinking it something like that I've spoke with other folks that have had similar truck just didn't know if the was a way to stop it and having the 3 speed tranny proly doesn't help