do you have a whistle sound coming from 3.4 v6 engine during acceleration?

I know that bug deflectors can create a whistle sound and sometimes it comes from the wiper blades. But in this case it's only under load. I would think vacuum leak.

 

I would thoroughly check the air box for small cracks. Also look closely around where it goes into the wheel well. Might be leaking there. I have seen quite a few 3.4 air boxes develop cracks on the backside where the MAF meets the box due to the engine moving and the box being mounted to the body.

 

thanks guys, it sucks because I cant do much testing sitting still so short of removing hood and riding on top the engine, its hard to track the exact location of the noise but it is under the hood somewhere

 

Does it make it when you put truck in gear holding brake and gas at same time to put a load on engine.

 

yes I went try it and I hear it but not as loud as when Im driving but the rear wheels keep slipping and foot on the brakes don't hold them in the grass.

if I do it on concrete with the parking brake on, I think it wont slip then but im not sure if I want to trust the parking brake to hold the truck enough to be able do this while i climb around and under the truck trying to find the noise, but it seams like a very very risky thing to do

 

Dont have any buddys that can help?

 

not very willing buddys, they are a lazy bunch of SOBs lol

I will have to hook it to a tree or something to do this but at least now, thanks to your good idea, I can recreate the noise (even though not as loud) without having to be driving it, so I can follow the whistle to the source.

I don't but, the best would be if I had access to a dino machine so I could safely replicate and trace the noise without fear of being run over and dying in the process lol.

 

Mine was the u-joint.

 

(Didn't read every comment on this thread)
Just went through something like this it was the intake manifold where the two peases come together the bolts were a little lose.

 

thanks, even if that's not it, its worth checking out knowing they "can" come loose

 

Mine does not whistle

Then maybe my hearing is so bad I can`t hear it

 

I'm hearing that same noise in my 16 taco

 

I heard it when I first got it but now I don't notice it anymore, im sure its still there and I just got used to it.

its not very loud at all and you have to have the radio off and listen for it to hear it, in the end I guess its just part of the design of the intake system that has that little sucking air whistle noise

 

My whistle was loose upper to lower intake bolts causing the metal gasket to vibrate. Get a can of carb spray and spray it around the intake to isolate. There is a large vacuum line set that is on the back of the block. It has a "Y" in it.

Some unsolicited advice from me... take the upper intake off to gain easlier access to the back of the block and check EVERYTHING that is back there. If the heater coolant hoses are older replace them while it is easy same for the small ones that go to the warmup block under the throttle body.

 

Mine whistles also but it starting doing it when I put a k&n air filter in it. Only whistles when accelerating and under load

 

2 years later still whistling? Or more of a whining?

 

I had a similar issue throw a code in my ol' Dodge. I searched high and low for intake/vacuum leaks. even took half the engine apart and replace the intake/exhaust manifold gasket on that thing, just to put it back together and hear the same noise directly correlated to how hard i pushed on the accelerator. my loyal car fixin' buddy was out of ideas...says to me, "we had better call my dad on this one..."

(checks his watch)

"It's 3:30pm... which means he ain't sober. I'll call him in the morning then go fetch him and drive him up here."

Sure enough, five minutes under the hood, and he berets me for keeping my truck in this condition, but also located a pinhole in a fuel line that was suckin' air and whistling every time i hit the gas hard enough.

Different make and model truck... but same symptoms. I dunno... take a check under the hood for some crap fuel lines with a pinhole in em. Mine was under a cold box held on by 1 out of four screws that vibrated a hole in that fuel line.

good luck.

 

just noticed this thread started 2 years ago. meh. i still didn't see any advice to check a fuel line... might still help someone.

 

https://www.tacomaworld.com/threads/wtf-is-this-new-noise-my-3-4l-is-making.468986/

 

I notice mine is doing the same. Have u figure out the cause?