The feds and the LAPD pulled over a vehicle NBA YoungBoy was in this evening in Los Angeles and tried to serve the rapper with a federal warrant.

Once the car stopped, YoungBoy started running.  So the cops called in the K-9 unit and the hounds successfully tracked the 21-year-old down -- but didn't bite him.

He's now in custody and in addition to fleeing the cops, they found a gun in the car they pulled over.

As for the warrant ...

Last month, it was reported that the feds were still investigating him for a 2020 video shoot in his hometown of Baton Rouge which the cops had broken and confiscated 14 guns and 79K in cash.