Jeep decided that it doesn't want to run with the map sensor vac line connected , if I unplug it , it runs and doesn't stall , it doesn't have a fuel smell and doesn't blow out smoke like it normally would with the map vac line disconnected , if I plug it in it runs for 2-3 secs and it stalls . If I try to give it throttle it backfires from the intake and then stalls , I tried replacing the map sensor and it still did the same thing , I'm lost anybody know what it could be ?