Manual Transmission problems of the 2004 Nissan Sentra

In my 2004 Nissan Sentra se-r spec v with a 2. 5l engine/manual transmission, at about 69k miles the car suddenly experienced unstable engine idling and significant power loss. First mechanic found loose metal pieces in the intake manifold area, along with spark plug one fouled. Metal pieces were removed and a new spark plug was installed. Car ran okay for a few weeks, the same symptoms occurred. Mechanic removed intake manifold and found two power valves and their screws obliterated and scattered throughout the compartment in dozens of loose pieces. Metal pieces removed, power valves replaced, screws replaced and secured with lock-tite. Symptoms occurred for a third time recently. I went to the Nissan dealership and spoke to the service advisors; they ran the VIN and found a recall on 04 Sentra 2. 5l engine vehicles, specifically the power valve screws coming loose, causing unstable engine idling and power loss.