It's getting cool in the AM here in NC and when I start the truck to warm it up, I'm getting a deep throaty growl when it idles (fast and slow idle). Is it my new Power Pup, or does the EGR redirect into the cold engine to help with warm-up? I also can hear the turbo spool during high idle (Airaid intake), which I didn't hear when it was warm out.

 

is your exhaust brake turned on?

 

Tried both on and off and it's the same.

 

This is normal. The exhaust brake comes on automagically in cold weather to help warm the engine faster.

 

OK, thanks.