Recently, Safari on my iPhone started finding things I searched for using Yahoo! rather than the previously default Google search engine. Now, I’m not gonna’ hate on Yahoo! here. I actually left it for weeks so I could see the differences and nuances here and there. From the different way it displays movie times to image handling, I just didn’t exactly love Yahoo! (although it gets better all the time). So I decided to switch it back. If you decide to switch back, you do so by first opening the Settings App and then scrolling down to and tapping on Safari.
From the list of available options, select Google, Yahoo! or Bing. Then close the Settings app and you should be good to go.