2000 LHS infamous knocking, not timing belt, backfires when starts

2000 Chrysler LHS 148k miles
Car has a knock when started, hard to get started, backfires when started.
Already checked the timing belt and it is in time.
Any ideas?
The car has been sitting for 2 years and I replaced all fluids and battery then drove it 200 miles home. The next day is when this started.

Kim, have you run some fuel system cleaner through it yet? What about the fuel filter? Is the check engine light on? How long does the knock last while running? Did it knock on the drive home? Let us know, best of luck.

Thank you for the input. We ended up giving up and took it to a repair shop. Good thing we did, because it turns out we were wasting our time on it anyway :( . We need to purchase a new engine because the rocker arms needed to be replaced, 3 cylinders were broken, and the valves were bent. I assume it was because we drove the car after it had been sitting. Just changing the fluids was not enough. Lesson learned!! Thank you for your reply. I will use this forum from now on. Hopefully I will learn much more! Thanks again, James.

Not a problem, thanks for keeping me posted, an expensive learning experience but at least now we know.