1985 Cadillac Brougham cadilac rough idels and stalls

As I understand the car will not idle in close loop mode, when its in open loop mode it runs but not good. It will run for a couple of seconds in close loop and the engine will oscillate high and low 2 or 3 times then it will die. So I disconnected the MAP Sensor and the vacuum line and put it into open loop road, it runs fine, but gets horrible fuel economy of about 7 miles. I have replaced the oxygen sensor, the distributor cap, spark plugs and wires, 2 old vacuum lines. And it still isn't running right. Could it be the throttle position senser? I am at a loss.