The first Cars film had sentimental magic to it, and the second film had a certain comic charm by focusing on Tow Mater, but Cars 3 has really nothing new to add. That's my problem with it; it feels recycled. It tries to recapture some of the spirit of the first film, but it is predictable and just passable as entertainment.
I like the plot element of an aging Lightning McQueen trying regain his Mojo after being shown up by a younger, faster and more cocky rookie. He tries to get some professional training to get back into shape. The film takes a left turn half way through when we find out that his female trainer is a racing wannabe who never got the chance to compete. This reminded me just a little of Jessie in Toy Story II lamenting over what she had lost. The difference is that Jessie's song had everybody in tears, but here the story is barely interesting. This leads to a plot twist at the end, where guess what? She does get her chance to race.
Rocky this isn't. The story is interesting enough, but in no way special, and seems too familiar. I expected more from Pixar.