Uly, if the speaker is in the US at the moment, should it be "came two years ago"?

Поехал? Я ездил в США, был в в США.

Tatiana, yes. But Zoya makes a good point - doesn’t this mean that they set off for the US?

Олли, в том-то и дело, что он, похоже, не «ездил/был», он там живёт.
Uly, I think "set off" is correct.

Nothing's wrong with поехал.

I didn’t say it was wrong, I just feel that I mistranslated it.

Уехал. Два года назад я уехал в США.

Разве нет?

I think both поехал and уехал are possible, but they don’t mean the same.
Два года назад я уехал в США implies that he left a country he’d lived before and he wasn’t going to go back.
Два года назад я поехал в США sounds like the beginning of a story where anything could happen, including his returning to the country of his origin or his deciding to stay in the US.

The thing is we

The thing is we don’t know anything about context.