Strange sound, like miss, or?

[DA BIG ONE]

Put on a race muffler (straigh flow trough style) and notice at idle and off idle there seems to be a muffled sound like when a BB gas motor has a miss in one or more cylinders. Truck idles smoothly runs fine and has plenty of power. Only smoke is when I lay into it a little blk smoke then clears up and I'm in hyper space

What should I be looking for, or?

[DmaxMaverick]

What you are hearing may be "turbo chop". The turbine will break up the continuous purr of the exhaust pulses, especially at idle while it is spinning slow (relatively slow). My '01 Duramax does the same thing (Kennedy 4" w/ straight through muffler), but didn't with the OEM exhaust/muffler.

Have someone listen to the exhaust note while you loosen injector lines one at a time. If one cylinder makes it go away, you may have an issue.

[DA BIG ONE]

Have someone listen to the exhaust note while you loosen injector lines one at a time. If one cylinder makes it go away, you may have an issue.

The sound is more like a BB with radical cam and slight miss sound, no knocking or metallic sounds.

What could I be lookin at if noise goes away when I crack a line?

[DmaxMaverick]

The sound is more like a BB with radical cam and slight miss sound, no knocking or metallic sounds.

What could I be lookin at if noise goes away when I crack a line?

The noise will be like a pronounced "puff". Kinda like a miss. No metalic or knocking noise. Some configurations do it, some don't. If you are hearing the noise through the tail pipe, it's probably just chop.

If you find an injector that makes the noise disappear, you may have a leaky or fouled injector (poor spray pattern). If so, the noise should have been present before the exhaust change, and there should also be a knock.

[Robyn]

It could also be due to fact that the 6.5 has a wierd firing order and along with the turbo.
Also the air is full flow in the diesel and this along with your Hog muffler will make some strange sounds.
The 7.3 strokes with strait pipes really sound goofy.
I think all is well and you are just hearing what the engineers heard and went OMG we got to silence that noise.
You should hear a 6.2 with big strait stacks, They are, well they are different.
Local fellow has a tow truck with 5" chome stacks on it and no mufflers. OMG the thing is awesome.

[DA BIG ONE]

I'm feelin more like it's not an issue now because I could not hear the same sound before this DynoMax race ultraflo. I'm happy the muffler is not loud under normal driving conditions, and it gives a nice BB gasser sound (not too loud) when I get into it.

The injectors are not old and are of the high pop flavor. I'll be cracking the lines anyway to be sure............

Thanks for the feed back!