CM2250 won’t boost over 20 psi

[Cpowers06]

Truck won’t build over 20 psi of boost, throwing a intake manifold temp sensor data erratic code after replacing IMAP sensor. Truck did have a failed EGR cooler that was prolonged before getting repaired... Also noticed what appears to be crusty soot on the outside of EGR valve right below where the bottom of the shaft for the butterfly would sit like a possible crack in the casting, anybody ever seen this? Thanks in advance!