I keep having this reaccuring problem. I live in CT so right now the temps constantly around 35degrees. I let my truck warm up for about 15 mins every day. Then go to drive. It drives fine, but every time at cruising speeds or about half throttle i get this buzzing or sucking for air noise. I cannot pinpoint this noise but others have told me its because of my backpressure. I have a K&N intake and a 3" downpipe to 3.5inch hollow exhaust. I dont understand why i wouldnt have enough backpressure. I am really worried because i want to put stacks on this truck for spring time.. Can anyone give me any ideas of what the problem might be?

 

it sounds like the exaust back pressure valve is closing while your driving it.

the ebpv is on the exaust side of the turbo theres a rod that goes to a lever on the exaust outlet and the rod goes into the turbo pedistal. under the intake side of the turbo theres a 2 wire plug. you can unplug this valve while the truck is off and drive it and see if it dosnt do it anymore.

 

I'm having this same problem, ford has a service bulletin about it but doesn't have a way to fix it, I was told you can't unplug that by the ford dealer. Is this cause it messes something else up or because of an emissions problem if you unplugg it?

 

Won't hurt a thing if you unplug it. Its their to help the engine warm up faster, but I gutted the valve completely and have noticed no difference in warm up time.

 

Thanks for the info, Mine only does it whens its really cold. I'll just disconnect it now. Again thank you.