I searched, but didn't quite get my question answered.

Can a variable resistor be responsible for a car idling fine cold and gradually stalling as the engine warms up? I checked mine and Terminals A-C = 4.73k-Ohm which is out of spec. according to FSM while Terminals B-C = 648Ohm which is fine.

 

Well, it is out of the specs according to the manual. So what do you have to lose by adjusting it??? Playing with it? Fiddleing with it??? Nothing is the answer.

With everything connected up, measure the output voltage on the plug. Write it down. Its the Green/Black wire. Now you will be able to return the setting back to this setting if you get confused while turning the screw. Nothing lost so to speak.

So follow the instructions in the manual. Its under Idle Speed And Mixture. They have you install the initial set coupler to prevent feedback from the bac circuit. The adjusting of the screw will have an effect on the mixture whether or not the initial set couple is installed, though.

Its self explanitory what the R and L stand for. Frankly its not a big deal if you screw the darn thing in a gentle manner and don't crank the screw past its stops. Like I said, you can always return the screw to the setting it was at prior to your messing with it.

Do fully heat your engine up prior to setting the idle, messing with the variable resistor etc.

And if you watch the voltage at the variable resistors output to the ECU it should vary smoothly b/t 1and 4 volts. I vaguely remember mine, on the N/T being somewhere close to 2.65 or there abouts. Varies from car to car. That's not a reliable figure for every car. Just a general idea of what it might be.

 

Every Variable Resistor I have had In my hands have been out of spec...I think that this Is a component that tends to go "bad" or fall out of spec often. Anyone measured the resistance of their VR lately? What did you see?

Is good?