Strange buzzing noise!

Hi all,

I've searched around for an answer to this already, but to no avail.

My 03 X-tra v6 emits a loud "buzzing" noise when the engine reaches roughly 3,200 rpm. The noise continues only until about 3,400 rpm and then disappears.

It happens when the engine is both warm and cold, and I haven't really pinpointed where it's coming from. Although the other day, my girl drove it up the street and it sounded like the buzz came from around the middle of the truck (so it may not be engine-related).

A buddy of mine who's an aircraft mechanic suggested (without really having a good look) that the noise could be a loose/rusty heat shield that's vibrating when it reaches a certain frequency.

Either way, has anybody heard of or experienced this mystery buzz before?

Any advice will be greatly appreciated.

 

oh the things that ran through my head when i seen the title of this thread......lol

 

Could it possibly be an up shift buzzer? I drive an Auto so I don't know if the Mans have this feature or not...my old RX7 did though...but only buzzed when i had the rpm's up aroung 8k heheh...

 

I'd also guess something is vibrating somewhere... you just gotta find what's loose. Mine makes all kinds of vibrating noises in the dash. I doubt it's a shift buzzer.. our trucks aren't that sophisticated haha.

 

Thanks for the replies, fellas.

I hope it's just something that's loose and not my cylinders threatening to explode or something insane like that.

The noise, whatever it is, just buzzes for a second and then ends as the rpms climb higher.

Anybody have any ideas as to where it could be coming from? I inspected my drive shaft and catalytic converter portion of my exhaust and didn't find anything.

 

I think I've heard of gas tank skids being very susceptible to rust... might wanna check that. Just start grabbing stuff under there and yanking. If it wiggles around, it could well be the culprit.

 

You know what? My gas tank skid is a pretty rusty sucker. I've been thinking about replacing it lately...and come to think of it, that's roughly the area I heard the noise coming from!

Having a "duh" moment here...

Thanks for the suggestion. I'll let you know if that's the cause.

 

Please do... it'll be the first time I've been right on here...

It's finally happening

 

I have the same issue, I believe it's the front cat's heat shield. Tapped it with wooden handled hammer end and it rang slightly, mine's pretty rusty however so I am gonna need to get a mini torch to apply some heat to break the rusted bolts free.