Been noticing a new noise that would best be described as a groaning sound. Seems to be the loudest near the drivers side under the dash or floorboard area. I haven't been able to hear it from under the hood.
It happens if I accelerate somewhat hard then letting off the pedal is when I hear it. Sometimes a few seconds and sometimes longer. Occasionally just letting off the accelerator at slow around town driving it will also be noticable then will stop.
Oh yes, the EX is a 2003, 2wd, 6.0 with 101,000 miles.
Any ideas of where to look?
Thanks to all of you for your help.

 

Give this video a listen and see if it sounds like this?


VID 20130121 00008 - YouTube

The was my ex when I let off the go pedal just lasted a few seconds as I let off. But mine was actually the rear drive shaft but you could hear it in the floor. I would describe mine as coming from under the dash though. So not sure if this is close to your sound or not but worth a shot.

 

Are you sure it isn't the Turbo "Farting"? The 6.0 does not utilize a waste gate, and if your boost is high when you take your foot of the throttle, it will spit the boost back out the air cleaner.

 

I'm sure it's not the turbo. sounds like it could be coming from some type of pump. The noise is most noticable from the driver seat, sounds like it's coming from near the floorboard area but doesn't continue long enough after I stop driving to be able to track it down.

 

Has it been into the dealer recently? I heard they like to update things like ficm programming without knowledge. Maybe they installed pain sensors?

All kidding aside can you get a video clip for us to listen to?

 

The fuel pump for 6.0l's is on the frame rail under neath the driver floor.

 

Might be exhaust or downpipe pipe rubbing.?

 

I have vacuum line problems and it causes my truck to make an eerie sort of howling sound sometimes, at least I think it is the cause of the sound.