Having trouble with a 87 4WD with 22R engine. It is idleing too rich. Smokes black smoke and rough. If I rev it up it will clear up and run pretty good. I think something is sticking , because sometimes it will clear up and idle fine and will do it until it is stopped and cools down again. Can someone tell me where the choke pull off is and how to check it? Part 2 How much trouble would it be to convert it to a TBI. What all would I have to change, or is it so much that it is not pratical. Thanks Charles