these two sites claim to have the fix:
https://obd2pros.com/dtc-codes/p050d/
https://carscounsel.com/p050d-code/
I'd just be sure you don't over tighten the manifold mounting bolts- the gaskets there deform very easily and create a leak if over tightened. You need to tighten in an alternating pattern and they max out at 89inch/pounds. MSD recommends doing this in at least 3 passes sequentially tightening until they're 89. They also recommend blue loctite on those bolts.