Whistling sound from rear of truck when accelerating at hwy speeds...

[krott5333]

It may do it at lower city speeds, but it could just be drowned out by the sound of the engine.

When I'm cruising on the highway, and give it gas, i hear a faint whistling-type sound from the rear of the car.

Is this the fuel pump? Is this normal?

[Fafdawg]

I had the same whistling type sound on my 2001 Qx4 when I accelerate on the hwy. It was Muffler leak. Right before the rear muffler was separated. You might need to put you hand on the muffler when the engine is on for 2-3 seconds to see the back pressure. Good luck, I got mine fixed 4 months ago. no whistling sound and i have a lots more HP. I Hope this help.