I am studying how to change the spark plugs in my 2007 Sonata Limited. I have a service manual and some websites have good instructions with diagrams and pictures, but both of these sources do not tell you clearly how to remove wire connectors. The service manual just indicate pressing tabs down and pulling. However some connectors are not that obvious. I attached a picture of the O2 sensor behind the surge tank. Can somebody give me some instruction how to disconnect these types of connectors? Thank you.