I was on my way home from work yesterday on the highway. When I would hit 2k rpm, I got this real loud whistle that "sounded" like it was coming from behind the inst. panel.

I don't have a boost gauge, yet, so I don't know at what level it starts. As soon as it drops below 18-1900 rpm, it's gone. It stays with me from ~2k to at least 2500. Had to let off. cops around here frawn on 85-90 mph on the highway.
Any ideas?

 

A boost leak at the tubing coming out of the turbo before the air filter???
Maybe a boost leak at the intake horn????

 

The regulator where the heater hose comes out of the block will sometimes go bad and cause a whistling sound.

 

I'll check that was well...
Off topic...
Long time no hear fearless leader!
I need to take pics of my engine bay. Did LOTS of work under there last weekend.

 

I finally got around to cleaning mine a little................

 

I checked all the turbo hoses and bolts. NOTHING.
My son said it sounds like it's coming from under the inst. panel. I had him lay across the floorboard to try to locate the origin. I haven't tried squeezing off the heater hose yet since the sound appears to be coming from the other side, but I will be doing that today. Does not make the noise unless I am driving the truck. RPM that it starts changes depending on the gear I'm in. If in D, it starts at 2k, if in L, not until 2600 or so.
HELP?!?!?
Anybody else have things I can check??

 

When I removed the stock fuel filter assembly, I did not put the bolts back into the intake. It was leaking at the bolt holes. Gasket is fine. Put the bolts in with spacers to make up for the filter housing not being there, and all is good.