Lately my 1988 190E 2.3 has been stalling when I come to a stop or slowing to turn a corner. Oxygen sensor light comes on prior to stall at times. In past weeks I have changed Oxygen sensor, plugs, cap & rotor and Idle control valve. Yet O2 light comes on after driving a few miles and goes off and on intermittenly. At idle RPM flucuates from 600- 1100. Seems like a slight hesistation when hitting accellerator. Also put in trans (used) two months ago and has some hard shifting. I would appreciate any help or ideas to fix. I'm open to all suggestions. Thanks for any help!!