Turbo Problem

[Black05]

I need some diagnostic help. The truck runs fine, but when boost drops off while going down hill at 2000 -2200 rpm there is a loud drone/vibration? that disappears if you reapply the accelerator and reappears when you let off. There exhaust pipe is not touching anywhere along the body or frame. My thinking was that perhaps the VGT solenoid is malfunctioning or the turbo charger is malfuctioning. Any diagnostic help would be appreciated.

Bill

[Black05]

Any of the technicians (or others) care to chime in? Any suggestions/diagnosis is appreciated.

Bill

[ahurley]

sounds like it could be something loose around the pedistal or maybe pull tube and check for play at the turbo or it could be just a little carbon buildup in the turbo itself.