When Gatsby and Daisy finally reunite, it is a climactic (or anticlimactic) moment. After awkward moments and then a more meaningful reconnection, Nick leaves Daisy and Gatsby with the feeling that this dramatic, triumphant moment was also marked by a sense of doubt.
As I went over to say good-by I saw that the expression of bewilderment had come back into Gatsby’s face, as though a faint doubt had occurred to him as to the quality of his present happiness.
There are two more dramatic climaxes in terms of the action in the novel. The two climaxes are causally connected so you could incorporate them into one. The first climax occurs when Myrtle is killed by the car which Daisy is driving, and Gatsby is her passenger.
The other car, the one going toward New York, came to rest a hundred yards beyond, and its driver hurried back to where Myrtle Wilson, her life violently extinguished, knelt in the road and mingled her thick dark blood with the dust. (Chapter 7)
The second climax occurs when George Wilson, thinking Gatsby had been responsible for killing his wife, Myrtle, goes to Gatsby's house, kills him, and then kills himself.
It was after we started with Gatsby toward the house that the gardener saw Wilson’s body a little way off in the grass, and the holocaust was complete. (Chapter 8)
To protect Daisy, Gatsby made no attempt to say he was not driving the car.