1988 Dodge Truck Motor loading

Have you replaced the O2 sensors? Have you checked to see if the catylatic converter is plugging? I can't remember if the 88 had throttle body injection or a carb. I memory serves me right, it's TBI. If so, when the engine is loading up, check to make sure the tbi is spraying a fine cone shaped mist of gas to the engine and not dripping. If carb, make sure the choke flap is opening properly.

Let me know what you find.