ISX CM871. Boost issue...

Running across US 36 in MO yesterday I had to drop a half gear. I never have to drop anything on this entire run no matter the weight. WTH??

Start watching the boost and sure enough I'm peaking at 26-27 lbs. Check for boost leaks when stopped. Nope.

This morning it continues for about an hour as I roll up I-29 and then suddenly I have full boost again.. 35 peak, easing down to 33 and holds.

EGR system cleaned and charge air pressure tested less than 1k miles ago. No faults, no coughing, nothing.

Turbo is a reman installed before I got the truck. VG actuator appears to be original.. 673k miles.

Should I be looking elsewhere or am I "probably" correct that the VG actuator has thrown in the towel?

 

Yep. Cleaned all the sensors and checked the tubes when I did the egr system cleaning. I'm prob gonna grab a new imap tomorrow anyway. Mine's been in there for 230k and a bunch of cleaning. It cheap and cant hurt.