'99 Rodeo-Stalls at idle
 

My '99 Rodeo (3.2 V6) stalls at idle and feels like it is misfiring while driving. It only does this intermittently. I can drive fine for a while and then it stalls when coming to a stop. If I continue to drive it will stop stalling and drive fine again. It's getting terrible gas mileage. I've heard about problems with IMG's cracking was very common. It only has 60,000 miles. Today I just noticed the cat's. have been cut out. I live and drive in Mexico so emission problems are not an issue here. Somebody probably cut them out to sell for money. Does anyone have any suggestions and are the missing cat's. a problem with the O2 sensors that in front and behind where the cat's. where?
Thank You,
Drayton