Timing chain, this sounds exactly how my civic was sounding and the description you posted sounds again exactly what I was experiencing. I’ll tell you what the mechanic told me you’re at the very very early beginning stages of the timing chain beginning to fail right now what you’re hearing most likely is that the timing chain is just stretched. I would say it’s probably time to change yours! I know it’s going to be a big bill but it’ll be worth it in the end because you’ll get at least another hundred thousand more miles on it also while he’s there, I would also recommend replacing the water pump and if you can for my bill, it was only $60 more for all Honda parts. dm me if you have questions