Bad spark plugs can cause hard starting, no starting, poor fuel mileage, rough idling, engine surges, loss of engine power, engine misfires and/or rattling or pinging like noises coming from your engine due to the engine misfires.
Your vehicles engine needs good spark plugs to ignite the fuel properly so with bad spark plugs your engine won't run efficiently.
Spark plugs should be changed around 70,000 to 150,000 miles as a regular upkeep on the vehicle.