This is a regular verb. It follows the conjugation pattern of the verb falar.
Present:
(Eu) enjoo quando o carro faz curvas.
I get sick when the car goes around curves.
Preterite:
Ela enjoou no barco.
She got seasick on the boat.
Future Subjunctive:
Se você enjoar, me avise.
Se enjoares, avisa-me.
If you get sick, let me know.