I don`t think the shop you took your car to was very knowledgeable. Did you mention to them that you reset/cleaned the potentiometer or did they come to the conclusion that the air meter was out of adjustment on their own? I know some other posts indicate you can set these by yourself. From what I have read, the concensus seems to be that you can not.
Also, from what I have read/been told, the CIS computers almost NEVER go bad.
The voltage from your O2 sensor should fluctuate. They can get fouled or burned out. If you are seeing mv in the 0.1 to 1.0 range from the O2 WITH the heater wire hooked up, it more than likely is alright. If it is stuck at 1.0 mv, I believe that is a rich condition. Where did the shop set your mixture? Did they say it was lean or rich? If the air flow meter/piotentiometer is messed up, the voltage signal it sends to the ECU will be off causing the computer to make attempts to correct. Have you monitored the voltage coming out of the air flow meter?? You can disassemble the connector on the #4 runner so you can monitor the voltage while your driving. I did this for a weekend and could not find any spikes or open curcuits in mine.
Do you own a volt meter with a duty cycle function? As Stevebfl writes about, you can check the system by monitoring the EHA amperage and the duty cycle readings. You will get a much better idea as to what is going on. If you get fixed duty cycle, the number provides you a hint where the problem lies.
Let us know.
Last edited by Tinker; 03-12-2003 at 01:35 AM.