So i have a question for anybody who can answer. i have the K&N 77 series CAI as well as a poweraid tb spacer. when i get in the throttle it has a good sound but when i level off around 2 grand rpm it has a constant high pitched whistle. not a good sound almost sounds like a belt squeaking is this normal on the 4.6? I am positive it is not the belts or pulleys it started after i put the CAI and TB spacer on. My question is,it normal to have such a high pitched constant whistle? Any ideas

 

Mine has a belt squeaking noise. I dont know what rpm i is though I dont have a tac. But my guess would be around 2 grand. Its hard to diagnose what it is because you have to be driving for it to make the noise. This is good news for you because it cancels out your mods being the problem.

 

I have an 06 5.4L w/ a CAI and Helix TB spacer. It also whistles. It is the TB spacer - they are notorious for it.

 

check to make sure nothing came loose, and everything has a good seal, clamps, gaskets etc, on my civic with the stock intake on it, the air box came loose right at the throttle body and had pretty much the same thing when cruising you can hear it but not at idle or accelerating

 

I agree - check everything. Use a little WD to make sure. But when your done and everything is tight - it WILL whistle. Get used to it or remove it.

 

Remove the TB spacer. They do nothing for power except the placebo effect and some additiional noise.

 

I think i will remove the TB spacer alot of people ave said the same thing.Thanks for all the input