190E Idle problems, fuel overload..

My 87 2.3 190E starts hard, idles bad, floods out like it is getting too much gas and not enough air. I have replaced fuel dist. fuel regulator, injectors, idle control valve. Get the car above 1200 rpms and runs like new? Have had system adjusted and spent hundreds trying to get this thing to run right, anyone know what controls the idle control valve? Is my computer going out? Can the voltage overload relay cause all this? Please help as I am at my ropes end with this.