What causes engine knocking when going up a hill?

Engine knocking when going up a hill is often caused by a combination of factors, primarily related to improper fuel combustion. This can occur due to low octane fuel, which leads to pre-ignition or detonation, where the air-fuel mixture ignites prematurely. Additionally, factors like insufficient engine cooling, improper ignition timing, or excessive load on the engine can exacerbate the issue. Maintaining proper fuel quality and ensuring the engine is well-tuned can help mitigate knocking.