When i let off the accelerator on my 6.0 i can hear a gas escaping or coughing type noise. This is most common once i installed the tow/haul on my superchips. I dont know if it is doing it on high perf. since i've been hauling my camper

 

Very normal on these motors.....no worry!

 

I posted this on "Ford Truck Enthusiasts Forums > Super Duty/Heavy Duty > 6.0L Power Stroke Diesel
Problem/mileage on 6.0’s to all owners!!


I have heard the same type of noise. I went to the dealer and he copied a page from there Oasis Special Service Message # 18155

Quote " Some 2003-2005 superduty F-series/excursions and 2004/2005 E-series vehicles equipped with a 6.0L diesel engine may exhibit a flutter type noise from the air box/intake area on deceleration. This noise typically occurs when decelerating after heavy acceleration. The noise ia a normal characteristic of this engine and has no impact on engine or tubocharger durability. No repair attempt should be made for this codition."

I'm sure you could go to your local dealer and get a copy for your own records.

 

Smokin
Just to add to what Rtoy posted, it is a normal noise that has to do w/ exhaust pressure/gases interacting w/ the VGT. The pressure has to go somewhere when it goes from being pushed out of the turbo at a high rate to a sudden recession of pressure. I have to think that this can't be good for the 6.0 but FMC line is that it is "normal". Only time will tell.