Unplug your gas range from the wall outlet.
Remove the burner grates from the top of the range. Remove the center caps as well.
Remove the mounting screws on the base of the burner that is sparking. Do this with your wrench.
Insert your putty knife under the top panel of the range, at the corners. Pry upward to pop the top panel off. Lift the top panel up to expose the burner assemblies.
Plug the range back in and turn on the range in question. You should now see the electrode, connected to the burner assembly, continue to spark. You will need to replace the electrode.
Turn off the range and unplug the power cable once again.
Unplug the electrode wiring and remove the electrode from the burner.
Fit a new electrode on the burner and replace the wiring.
Replace the top panel of the range as well as the burner caps and grates.