Hello everyone. I'm a new poster, but I've owned my 04 X-Type 3.0 Auto for about 8 months now. It has 53k miles on it, and this is the first problem (other than me breaking my passenger mirror falling on ice, which I fixed today) that I have had to deal with on this car.

For the past month or so I've noticed a very annoying whistle noise coming from(I believe) the frontof the car. It only does it when I am taking off or slowing down (around 10-15mph) and reving the engine doesn't change the pitch (while making noise, I tried going to nuetral to rev and see if it increased with the engine, it didn't). It isn't drivetrain vibration, as I've grown to accept the noise under the body from these AWDcars. The closest thing I can compare it to is a siren singing louder as you accelerate, and softening as you decelerate. I actually thought I was getting pulled over the first time it happened. Kinda like ground loop noise for the bass-heads, but I don't have anything other than the factory stereo installed. The noise, as annoying as it is, has taken back seat to the check engine light that came on yesterday morning... please keep reading.

I pulled into AutoZone today to get the codes, and they are as follows:

P0300 Random/Multiple Cylinder Misfire Detected
P1316 Misfire Rate Exceeds Emissions
P1111 System Pass

I'm changing the oil tonight (myself) and will be inspecting hoses, etc. for leaks (one post I read mentions a hose behind the manifold connected to the 'brake booster' that has a possible leak?).

My question to you experts is (before I go to the dealership to ask):
What should I pursue to fix the errors mentioned above?
Has anyone experienced vaccum leaks causing the check engine light to post?
And is my mileage (about 16.6mpg) the result of an obvious leak somewhere that could not only be causing the sound, but also the light?

Thanks for all of your help, I've grown to love this forum and the advice you guys offer.

 

Just a follow up (I hate finding posts where all (or part) of the problem gets solved and the poster doesn't give input as to what he/she did to fix it).

I continued with my oil change and added STP Complete Fuel System cleaner to a fresh tank of Shell premium gas. I then went back to autozone, and had them clear the error codes for me (for free) to see if things would light back up again. I've been driving it for the last 2.5 days, travelled nearly 130 miles, and I haven't had a problem since.

The annoying noise, however, still continues... [&:]

 

VC not a noise maker.. and it is part of the transfer case... that is a multi thousand dollar repair.

I wonder what he might have been referring too?

 

sounds like its the center bearing on the driveshaft especially if it is most noisey when cold.