YOU SAID:

im gonna grab some lunch u coming?

INTO JAPANESE

昼食をとるつもりですが、来ますか？

BACK INTO ENGLISH

I'm going to have lunch, do you want to come?

INTO JAPANESE

昼食を食べるつもりですが、来ませんか？

BACK INTO ENGLISH

I'm going to have lunch, would you like to come?

INTO JAPANESE

昼食を食べるつもりですが、来ませんか？

BACK INTO ENGLISH

I'm going to have lunch, would you like to come?