Dodge: question about my 1996 dodge truck

Question
hello! Im a completely dumb when it comes to vehicles and need some help. I got my truck looked at twice and no one know's exactly what's wrong. one said it was the Cadillac converter. but another says its a sensor. I wanted to know if anyone knew what kund of sensor it could be?

Answer
mis holly  unless u provide me with some diagnostic info  or codes or anything like that   I have no way of knowing whats going on. Im not there to look at teh truck so  this is like asking a DR whats wrong with you when u have not told him any symptoms