I can start the car, but when I turn the key, the car sounds weak. I am not sure what I should replace: the battery, starter, spark plugs, or something else.
If the vehicle sounds weak when you turn the key, as in it cranks slowly, or struggles to turn over, then it is most likely a battery or starter issue. I would have the battery load tested to make sure it is putting out the proper amperage to start that vehicle. Old or worn batteries will eventually weaken over time and need to be replaced. If the battery checks out then I would suggest testing the starter. A qualified technician from YourMechanic should be able to conduct a loss of power inspection with a battery load tester.
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