Green’s Dictionary of Slang

(US) a car that has been lowered and otherwise customized for teen use.

1981		E. Bunker Little Boy Blue (1995) 206: The fuckin’ heat stopped us [...] Just ’cause it was five vatos in the ranfla.
1993		L. Rodríguez Always Running (1996) 55: Anybody recognize the ranfla?
2003		in Urban Dict. 🌐 ranfla. Spanish name for a lowrider or a old ass fixed up car...preferably Chevy. ‘Mira, look at my new ranfla’.