You're hearing what's known as "detonation", which is caused by the fuel-air mixture igniting instantaneously, rather than in a controlled, smooth burn. Since its pressure spike arrives way too soon in the cycle, the pistons are hammered back down in their bores before they've reached the top. Bearing loads and cylinder pressures go through the roof!
The octane rating of fuel is a measure of its resistance to this phenomenon. Assuming something else hasn't gone wrong with you engine that would cause this to happen, try running a gas with a higher octane number.
check CV joints
It's really hard to understand what you're asking here."What causes a knocking sound when your car drops into a hole while driving?"If that's your question, I imagine that it would be the sound of your car dropping into a hole.
Gasoline pedal/air intake pedal
you could have a wire broke in the tire
The failure to step on the brake pedal or if manual the failure to step on the clutch The transmission or gearbox is not working properly
Shift to reverse
it really is a vague discription. do you feel the tick in the gas pedal? does it sound like its coming from near your tires... or your engine? most likely it is a wheel bearing or bushing. if it becomes a knocking noise when you go around corners it is your constant velocity axle i am assuming your vehicle is a front wheel drive.
In general flip flops are safe to wear while driving. However they can become a danger if they slip off and get wedged under the gas pedal or brake pedal. Wearing them while driving is not recommended.
tie rods
The emergency brake is partially depressed, even though the brake light is not on. release with handle and pull up on the brake pedal.
The knocking noise could be one of several things. The wheel bearing, a worn steering or suspension part, or road debris could be causing the noise.
Answer: "Riding the clutch"