My 03 6.0 has been running good till lately. Little by little it's losing power. It starts and runs fine. Normal driving, feels ok. . .not as powerful as I'm used to but I just figured I'm looking for more. I had another adII go bad so on stock fuel pump for now till I can mount sump for replacement ad pump. Normal driving doesn't seem unusual. Idle is fine, goes down road fine, no misfires or anything odd. Little less whistle from turbo. . If you try to pass someone boost goes to 30 psi and lotta growl from exhaust and a little smoke from tailpipe but no *****. Barely gets out of its own way. 210,000 miles, stock original injectors. I also have a humming sound like a power steering pump going away but only at driving speeds. Is a trans problem possible? It seems like the php tune in my ficm isn't working? I'm wondering what to look for when I get hands on a scanner to check further. I have pocket scan tool which says no current or pending codes. Mods are listed in sig and I'm pretty sure I have good alternator and batteries. Any ideas on where to look would be appreciated.

 

You should pull your intake off the turbo and spin the turbo, it should spin freely. If not you need a turbo.

As for the growl from the power steering, I hate to say it but it needs replaced, I had the Same power steering issue a few months ago, except mine totally died a week or so after it started growling, a bottle of Lucas trans repair will extend it's life for a short while.

 

If the guy did even half that stuff to his truck himself in his SIG im pretty damn sure he can figure out that if his turbo don't spin freely that its bad!! Good god man
But anyway adrenaline junkie check lift pump on frame when these go bad nobody knows because you'll still suck fuel from tank..let me know hoss

 

If you got anyway to check fuel pressure might also want to check exhaust uppipe for leaks or a possible seperation

 

I got a scan gage and checked hpop output. It was low at anything above about 1000 rpm. It was just past it's useful service life and couldn't build enough pressure. I got a diesel site HPOP and problem solved! I had fuel problems a while ago and actually permanently mounted a small 100 psi fuel gage right in the test port on filter bowl. Was cheap and easy!