OK; being a "Car Guy" (and an older one at that) you would think I wouldn't need to ask this question; plus you would think a simple Google would get me the answer, well neither of those attributes have worked.  I recently obtained a (Concourse Condition - My Opinion) One Owner, All Original, 20K Mileage, Garage Stored 1985 Dodge V6, 4 Speed Prospector Pick Up; and absolute beauty.  So as I began to change fluid, filters and get her running, which I did I noticed as she was idling, right under the exhaust manifold and "Air Pump" was a small, which looked like a "mini catalytic" convertor getting RED HOT; I shut her down and realized that something was blocking the exhaust (?); so I am in the process of working back, muffler, catalytic convertor (which there is one under the truck) and see if after all those years in the garage some critters decided to move in; BUT..................My question:  "What is that small cannister that is turning Red Hot, not why but what is it.  I'm going to attempt to download a pic, hopes it comes out, hope someone knows and replies; thanks.  JPL ... View more