2005 Duramax Diesel P0237 and P2229 Error Codes After Engine Overhaul

I recently completed a full engine overhaul on my 2005 Duramax diesel with the 6.6L V8 engine. The engine is now running, but I'm hearing a noticeable thumping noise coming from the air box. The check engine light has triggered two diagnostic codes: P0237 (low boost pressure) and P2229 (barometric pressure sensor malfunction). Based on these symptoms, I suspect that one of the intake valves is not seating properly, leading to compression loss and air leakage into the air box. Before disassembling the valve covers, I wanted to seek expert advice to confirm this diagnosis. Any insights or suggestions would be greatly appreciated. I'm new to diesel engine troubleshooting and appreciate any guidance from experienced users.