What is a common sign of a failing fuel pump?

A common sign of a failing fuel pump is difficulty starting the engine. The fuel pump is responsible for delivering fuel from the tank to the engine at the correct pressure. When the pump begins to fail, it may not supply enough fuel, leading to insufficient combustion in the engine. This can result in hard starts, where the engine cranks but does not start easily or requires multiple attempts to fire up.

The other symptoms listed can be associated with different issues: increased engine temperature often indicates cooling system problems or engine wear; persistent knocking noises may point to issues with the engine's internals like rod knock or low oil levels; and white smoke from the exhaust can suggest coolant entering the combustion chamber, typically a sign of head gasket failure or a cracked engine block. Therefore, the difficulty in starting the engine is a more direct and specific indicator of fuel pump issues.