Cummins ISM not reading boost correctly?

[Mikesuburban1]

(02-24-2017 )in2trux Wrote:  Did you replace the turbo actuator too? A sticky actuator or the air valve that controls it can cause these symptoms and is many times the problem, not the turbo. It could be going into silent derate.

Did you replace or thoroughly clean the egr valve? Sticky egr will cuase this problem too.

I replaced the egr with a new one and the new turbo came with a new actuator. I have a mechanical boost gauge that i tapped into the intake horn right before the manifold. The turbo seems to spool fine the boosst gauge reads 38lbs but the sensor and ecm are reading 31.5lbs and sometimes it will read correct and power comes back