2010 Cadillac CTS4 P0008 and P0342 Faults: Diagnosis, Fix Attempts, and Timing Chain Concerns

I recently encountered both the P0008 and P0342 diagnostic codes on my 2010 Cadillac CTS4 Premium with a 3.6L Direct Injection engine (99,000 miles). The car has been well-maintained with all original options including Recaro seats and is a beautiful black vehicle. Initially, I received the P000-8 code (related to the B1 sensor/actuator), so I replaced the camshaft position sensor and actuator. However, after installation, the P0342 code (camshaft position sensor malfunction) appeared. The new cam sensor was sourced from Amazon and appears to be of lower quality—during testing, I noticed a significant drop in signal strength compared to the original sensor that I removed. This may have contributed to triggering the P0342 fault. I also replaced the B1 solenoid actuator with an A/C Delco part as a potential fix. The original cam sensor was cleaned thoroughly before reinstallation, and I changed the engine oil with Risolene additive. Upon inspection of the B1 area, it appeared clean; however, the oil filter was noticeably dirty but not severely so. After driving for several hours on highways and in traffic, the P0008 code returned. I cleared the code and continued driving without immediate recurrence. The idle remains slightly rough at times, which is why I'm currently using Seafoam and premium gasoline, and I plan to install new spark plugs today. I don't have a full service history for this vehicle, but I suspect that the weak original cam sensor may have caused intermittent faults, possibly triggering both P0008 and P0342. I now have a backup sensor ready to test. A major concern is whether the timing chain might be failing—especially given that Cadillac discontinued extended warranty coverage for timing chains in 2009, even though the 2010 engine used identical components. This raises serious questions about long-term reliability and post-warranty maintenance. I'm currently exploring cost-effective parts first and hoping this is a sensor-related issue rather than a mechanical failure like a broken timing chain.