I searched but my noise does not really match what others describe. While driving at a constant speed (60 mph 1500rpm) I get a fluttering noise. If i go over bumps the flutter is more pronounced. It sounds the turbo whistle is actually changing pitch back and forth with a constant throttle and speed.

A little background. I had a hole in the lower intercooler boot which I replaced. Before I knew there was a hole I had heard a terrible fluttering noise that sounded like a bird going through the turbo when I was accelerating hard pulling my trailer.

I don't seem to have the performance or mileage I once had. There are no roads near the dealer which I could hold 60mph for a stretch and have a tech confirm and diagnose the noise.

Any thoughts?

Thanks, Tim

Can this thread be moved to the LBZ forum? Somehow I posted it here on accident.

Tim

Anyone, I have the same problem, The dealer keep telling me it is the VVT, Tonight I am going tot try to tighten all the connections again to see if there is a leak. Mine flutteres liek crazy when towing any kind of load. The wierd thing is I am still showing full boast on my EVO.

Anyone else??

Not sure if the duramax has the same stuff but on my PSD that I got rid of, I had the same problem. It was a faulty vane position sensor and/or bad exhaust back pressure sensor. One of the many reasons I lemon lawed it. It would turbo fart or flutter as we call it here, under constant load normally going up a grade and changing altitude. I'm surprised it's not storing a code.

any difference in power? Mine will do this and with the 5" turbo back you can really hear it. Mine sounds like something is opening and closing, will go from high whistle(turbo) to low rumble(gasser v8 rumble) then back again. This mostly happens when I first start it. But I am sure this is just the EGR or Turbo doing its thing.
This will also happen while crusing a constant speed. However there is no noticable power loss.

Mine does it too!! I took it to the dealer and they told me I was crazy. Well the truck didn't do it when it was new, and now it does. It sounds like a pressure cooker when you are pulling a trailer or a grade.