1986 190e 2.3 8 valve automatic

The car overheated got very hot, hose came off at top of radiator. The radiator inlet had crack so replaced radiator and thermostat. When car stopped at a stoplight had very rough idle. Once leaving stoplight car runs good no surging appears to fine fine until coming to a stop then has rough idle again. Replaced spark plugs, spark plug wires, distributor cap and rotor. Still has rough idle. Also went to auto wrecker and got a coil installed it still no difference. Put original coil back on. Your input please