I have a 2006 6.0, edge programmer, and egr delete. I had the hpop replaced back in July. I have a straight piped exhaust system as well. I have always noticed a loud whistle at idle from the turbo but yesterday when I started it there was not whistle at all. When I drove it it would still build boost but not like it used to. I have to really get on the throttle to build boost like it should. Is it my turbo going bad?

 

Welcome to FTE, Andrews6.0 . If you don't get some help here in the Super Duty forum, let me (or another moderator) know. We can move your thread to the 6.0L Power Stroke engine forum.

 

I would check your two blue tube connectors on the high side, especially the lower one, to ensure they're not leaking. I would also expect it to throw a code before long. If underboost, maybe your vgt unison ring.