Idle issues

[Giamanut]

I've been fiddling with an idle problem for awhile now and hoped to get it solved, but here I am. Typically idles high. When I start the car it's about 1000 rpm and when it warms up after a few minutes goes to 14-1500 rpm. I backed off the microswitch and idle screw but it stayed at high idle. I also checked the microswitch to ground and it is working properly.

I disconnected inner bulkhead on ECU and it goes to 2500. Unplugging the outer does not change anything. I tested the thermistor on the 4 pin bulkhead at the ECU and found resistance so assumed it's working. I also swapped it with another ECU I have that is known good and had the same results.

I checked around injectors and vacuum lines with carb fluid but didn't spot any leaks.
I checked the idle motor and it does hum. Also, just for good measure took it out and sprayed carb fluid in it and shook it around a bit. At one point I checked voltages on the idle motor connector and noticed 12 volts center pin, about 10 volts to one side but 0 volts to the other. I assumed that it was just not signaling one side at the time. The Lambda system does buzz.

I tested the Lambda Dwell with the engine warmed and the O2 sensor disconnected and got 44. (Using Orange wire and ground on the engine ground on the intake 4 cylinder mode)
The engine idles around 850 rpm with O2 sensor disconnected.

When I connect the O2 sensor the idle goes up to 14-1500 rpm and here's the disturbing part. The Dwell goes to about 84. I messed a bit with the air/fuel screw on the distributor and I can get the RPMs to drop to 800 but it smells like it's running to rich and wants to flood so I put it back the way it was. Also, that didn't seem to change the Dwell with the O2 sensor hooked up and I understand that it should be around 40, not 84.

In any case, the Lambda system is working very hard when the O2 sensor is hooked up.
Questions:
1.) Could a bad O2 sensor cause this because it does seem to be working.
2.) I didn't check continuity on all ECU lines, but unhooking it didn't seem to matter. I did consider that the motor might just stay in the state it was left in, and perhaps if one side's not working
3.) Any other ideas based on what I've done so far?

It really sounds like your air idle motor is is letting air by when it should not be. Try taking it out and plugging the lines use your thumb over the pipe of agony side and you can modulate the idle. If it is stuck open it is an vacuum leak.

[Giamanut]

It really sounds like your air idle motor is is letting air by when it should not be. Try taking it out and plugging the lines use your thumb over the pipe of agony side and you can modulate the idle. If it is stuck open it is an vacuum leak.

Also if you dwell goes up with the O2 sensor plugged in that means it is adding fuel because there is extra air. Extra air and fuel = more RPM! you System is working correct. When the O2 sensor is disconnected and you idle goes to 800 I am guessing you will see your engine temp go up because it is on the lean side! Don't want to be there!