In the 80's they started using "feed back" Carbs and started putting throttle position sensors on them. It was all about emission's, so not only do you have a carb you also have a ECU. Best thing to do is replace the carb with a real Weber or find a pre-85 carb. then strip out the ecu and the sensors it hooked up to. One of the worst cars for this "problem" was an 85-86 Mustang 2.3L, the carb base would loosen off and the thing would run pig rich as the computer saw a vacuum leak.