Classic/Antique Car Repair: 1986 chrysler new yorker tubo 4 cyl, chrysler new yorker, oxygen sensor

Question
my car has no power. i have replaced the map sensor,brain,plugs,etc. it will run when its in park but will lose power when its in gear.

Answer
It sounds very much like a plugged catalytic converter. A simple test is to remove the oxygen sensor. Then start the engine and see if it runs any better. If it does, removing the sensor has created a path for the exhaust to escape. Let me know the results.
Brad