Jeep Grand Cherokee P1391 Code: Rough Idle and Hard Starting - How to Fix?

Hello, my Jeep Grand Cherokee is running very roughly and has difficulty starting. I've received the P1391 diagnostic code, which indicates a loss of crankshaft position signal. I've already removed the engine heads and inspected the camshaft, but the issue persists. I need expert advice on how to properly diagnose and fix this problem. Any guidance or troubleshooting steps would be greatly appreciated.