Air Pump on an 86 Dodge D100

Sounds like the owner was too ignorant to understand what he was doing, too lazy to learn how to do a proper repair, and too cheap to pay someone else to do it, so he just hacked and slashed wherever he saw gol-durn 'mishuns crap, aHyuck! :roll:

Cats (meow?) and carbs don't generally play nicely with each other. Without the air pump, the catalyst will likely overheat and melt down internally, plugging up the exhaust flow. Was this '86 originally equipped with an oxygen sensor and feedback carburetor? They came both with and without in '86. The O2 sensor would be threaded into the rear wall of the exhaust manifold's central collector area.