1986 Dodge Ram 50 Bad Vacum Leak Find Place Rag Around Carb Will Run You Keep

DODGE RAM 50 BAD VACUM LEAK I CAN NOT FIND,PLACE RAG AROUND CARB IT WILL RUN IF YOU KEEP MOVEING RAG AROUND INSIDE CARB BUT HAS VERY LITTLE VACUM WILL NOT SUCK RAG INTO CARB FINALLY GOES DEAD ,WILL NOT RUN WITHOUT RAG.WHERE DO I LOOK FOR VACUME LEAK.