Fuel System: Apart from the fuel pump, there could be other components in the fuel system causing the issue. Consider checking the fuel filter for clogs or restrictions. A dirty or clogged fuel filter can restrict fuel flow and affect engine performance.
Ignition System: Although you mentioned changing the plugs, ensure that they are the correct type and properly gapped. Additionally, inspect the ignition coils and ignition cables for any signs of damage or wear.
Air Intake System: Check the air filter to ensure it's clean and not obstructed. A dirty or clogged air filter can restrict airflow to the engine, affecting its performance.
Engine Sensors: Faulty or malfunctioning sensors, such as the mass airflow sensor (MAF) or oxygen sensors, can impact fuel efficiency and starting performance. Consider having these sensors checked and replaced if necessary.
Battery and Electrical System: Ensure that the battery is in good condition and the terminals are clean and secure. A weak or failing battery can cause starting issues. Additionally, check the alternator's output to ensure it's charging the battery properly.
