Does a 1991 Ford Taurus use the old freon or R-134a?

Unless It Has Been Refitted For R134 It Will Use R12. Best Way To Work This: Have A Good A/C Tech Update To R134 And Test Your System. You Will No Longer Be Able To Get R12 Well Some People Have Some Stashed About ( Cost Is High ) There Is Supposed To Be A Freon That Will Mix With R12 But I Have Heard That It Will Not Cool As Well. Good Luck