check engine light

i was told you could jump a and b on the ecu to read the codes but i dont know which one is a or b is there any pictures or can anyone decribe it for me. i also have a problem that others have but have seen no answers when my car is freeway speeds and a speed is held steady in will start to shutter once i let off and press the gas again it goes away (94se bonn) could it be the tps or tcc and does any damage occur if i drive with the tcc disconnected.