Code P0016?

I replaced the cam and crank sensor but still the code is up. Changed the engine oil as well but still the code is up. The problem I see is hard start and during a cold start there is noise little rattle for a minute and then it goes fine. And noise comes from the engine when there is load on engine like driving uphill. Not when the RPM is high but when there is load on engine. Tried to inspect the timing chain by removing engine cover. It's very hard to see but feel like it jumped a tooth but not sure as it's very close to 10 and 2 timing marks. And during this for a second the timing chain was loose. So my only fix is replacing the timing belt? Please help Engine Oil.

And another thing the car has a 2009 2.4L engine which has a VVT, engine of cobalt and 2008 doesn't have a VVT so the ECM may not know VVT but the code was not showing up earlier I drove 3-4k miles with the code but had no problems except the noise I mentioned.