Here's why:
* Restricted Fuel Flow: A clogged filter restricts the flow of fuel to the engine. When the engine is idling or under light load, the fuel pump might be able to supply enough fuel, but it might not be enough for higher demands.
* Pumping the Pedal: Pumping the gas pedal increases the throttle which increases the demand for fuel. This momentarily increases the pressure in the fuel system, forcing more fuel through the partially clogged filter, allowing the engine to run. Once you release the pedal, the pressure drops and the restricted flow becomes insufficient again, causing the engine to stall.
* Other Possibilities (but less likely if pumping the pedal works): While a clogged filter is the most likely culprit given your description, other potential issues could cause similar symptoms, including:
* Weak fuel pump: A failing fuel pump might not provide sufficient pressure even when pumping the gas.
* Clogged fuel lines: Similar to the filter, blockages elsewhere in the fuel system can cause intermittent fuel delivery.
* Ignition problems: While less likely given the symptom, ignition issues could also cause stalling, but pumping the gas wouldn't necessarily fix it.
In short: A clogged fuel filter is a strong suspect, especially since pumping the gas pedal provides a temporary fix. Replacing the fuel filter is a relatively inexpensive and easy repair, and should be your first step in troubleshooting this issue. If the problem persists after a new filter, then further investigation into other potential causes may be needed.
