Which one is correct? 1. I went to do something Or 2. I went do something We use "to" between two verbs in present sentence, but I don't know about past sentence?! Thanks for helping
You must use the to. That's not "two verbs in present" but one tensed construction (go or went) and one infinitive (to do ...) as its complement. The idiom requires that the complement be cast as a marked infinitive, regardless of the construction used for GO—see Colin Fine's answer.
Similarly, went doing ... presents a tensed verb with a gerund-participle—not a "present progressive" be carolling—as its complement.
We go caroling on Christmas Eve.
We went caroling on Christmas Eve.
We have often gone caroling on Christmas Eve.