I periodically have been hearing a kind of whistling noise in my cab, it seems to hinge on the pressure I have on the gas pedal and if I tap the pedal it gets louder and goes away as soon as I'm off the gas. It has only occurred in cold weather and only when I first get going with a cold engine. The only modifications made is a custom dual catback exhaust and the air filter to a K&N. The problem doesn't really worry me but it's a little annoying and wouldn't mind putting some time into eliminating it if any one has ideas. Thanks

I've got that exact same problem. Replaced the PCV valve and it subsided for a few days, then came back again worse than ever. Now I also noticed some power steering fluid leaking and there is a rattling sound coming from the power steering pump area. My next step will be to replace the power steering pump. Maybe that is the problem.

I have a 2003 Dakota CC with a 4.7L, I have been having this issue for the past couple of months. Seems it started when the weather got cold (northwestern PA winter). I have cleaned and checked the TB and IAC for cracks or leaks, along with all of the vacuum lines. The noise occurs while cruising with the RPMs between 1500 and 2000. Also, my mileage has dropped from 17MPG down to 14MPG, so I suspect that there is some sort of vacuum leak causing the problem.

I will be keeping an eye on this forum to see if anyone comes up with a solution to this problem.

Thanks for all the input guys, my whistling has cut back quite a bit lately. I'm still under warranty for another 2,000 miles so I'm going to have the dealer look over everything in the next couple of weeks. I'll let you all know if they see anything.

How did you fix it??????????????

Well, I replaced the power steering pump, but the whistling sound is still there. Like others have mentioned, it is more frequent when the weather is cold. Hmmm... There has to be a fix/solution/explanation for this.

Sorry no news yet, been too busy to get to the dealer, although an update my check engine light has come on, haven't gotten scanned yet but that'll probably get done this weekend....so hopefully I'll have something to post next week.

Got my truck checked over at the dealer today, they replaced a hose that had cracked near on the EVAP system and said that that had probably been the cause of the whistle....but I guess I probably won't know for sure until next winter.

Thanks for the info. Can you please tell me where the EVAP system is?
Appreciate the info.

On the underside it's about half way up the frame on the driver's side, its a big canister with a bunch of hoses connected to it.

I have a 2004 dakota w/ the 4.7 L V8. I bought the truck from a dealer and replaced the stock air intake with a 77 series K&N cold air intake. The wistling, I belive, is caused by the intake system. I dont know what part of it. But it did not do it before I replaced the intake. I think it has somthing to do with the air traveling through the exhaust gas return back into the intake? (w/e the black tube was that you had to cut and place over the small opening on the backside of the intake tube, not the sensor, but the tubing) I'm not sure. Just an Idea.