Car that stalls when idle and at stops?

Our Impala with the 2.5l ecotec stalls when idle and at traffic lights, has hard starting and rough low idle. Codes showed to replace cam shaft position sensors, we replaced both along with the vvt solenoids with no results. Also changed the oil at that time as well. We also cleaned the rocker arm solenoid and found bits of plastic, same when we removed the vvt solenoid. There is a ticking sound but it is coming from the back of the engine, and not where the timing chain is located. Does it still sound like a timing chain issue? Or should we also try replacing the crankshaft position sensor as well. Video included of engine running.