1988 190e idle problem
 

i made the mistake of trying to correct idle problem by adjusting fuel mixture. end result is my engine idles about 1200 rpm when warm. i have changed all hoses around the rotary air device and cleaned air device. it only made it idle higher. the duty cycle at pin 3 is about 79 percent. if i accelerate to about 2000 rpms and drop back to idle the signal drops to 49/52 percent then builds back up to 79 percent. the voltage to the idle device seems to vary between 0 and 13v. i checked current flow and it is zero. the contacts on the idle control read about 20 ohms. HELP

i found an intermittent connection on the rear sensor at the front of my engine. the one with two separate wires. don't know what it does but soldering the wire directly to the pin changed my x11-3 duty cycle from 79 to jumping between 52 and 28 percent. this lowered the idle speed but it still gets lower with air cond and drive/reverse. i think i have made a step forward but i'm not home yet! any ideas?