Hi tech's just wanna know What cause negative fuel trim at wot? i know some reasons just tell me if i am wrong ok.

1)bad 02 sensor-just heard 02 internal leaks cause this

2)stuck open egr valve

3)ruptured fuel pressure regulator

4)stuck open injector

5)retard timing-can anyone explain how this leads to Rich fuel trim at wot

any other reasons and explanations are welcome here->

Deen Jhons
Educator/Instructor
Deen Motors
Kandy Matale, Sri Lanka