How do you replace the spark plugs on 1999 rx300 Lexus?

To replace the spark plugs on a 1999 Lexus RX300, first ensure the engine is cool and disconnect the negative battery terminal. Remove the engine cover if necessary, then carefully detach the ignition coil connectors and unscrew the coils to access the spark plugs. Using a spark plug socket and ratchet, unscrew the old plugs, checking for any debris in the cylinder head, and then install the new plugs, tightening them to the manufacturer’s specifications. Reassemble the ignition coils and connectors, reattach the engine cover, and reconnect the battery terminal.