Go sour phrase informal figurative
To become less pleasant; turn out badly.
It seems that their relationship is going sour.
We have dated for two years and now everything has gone sour.
The truck with the speakers almost hit us. It almost did go sour.
To be put in a bad mood
Used to refer to an unpleasant, repellent place, thing or person
To be difficult, troublesome, or unpleasant for someone; to be to someone's disadvantage.
The verb "go" should be conjugated according to its tense.