cause it's junk
a fuse!
possibly hitting the front bumper
I would check the suspension bushings, if one of them is worn it would cause a knocking noise.
Probably a rotted exhaust pipe has broken off. Take the car to a muffler shop for repair.
Yes it does. So it's best to replace the timing belt at recommended intervals. Waiting till it breaks could cause serious engine damage.
A hole in the muffler would cause a knocking sound in your muffler. A loose exhaust pipe can also cause a knocking noise.
It will sense the engine pre-detonating fuel(usual cause is fuel octane level to low). ECU will adjust timing to prevent damage to engine.
Yes, just about any worn suspension bushing or other wearable part can cause that type of noise.
Most likely you need a new strut
Loose, worn, broken tie rods, sway bar links, struts, ball joints,.......
Subaru sucks. why the hell would you want a Subaru, especially the cheapest Subaru cause they all blow.