So Ive been fighting this idle issue for some time. I followed the idle surge checklist to a T a few times and pulled codes KOER and KOEO and get an 11. Did a cylinder check and everything turned out fine. I finally gave up and took it to a friend whose a mechanic and has been in the mustang scene longer than Ive been born.
The car was only surging at a stop and would drop down to 300 rpms and surge up to 900. He fixed that problem but not completely. Upon start up it surges for a couple seconds then levels out although he had to set the idle to 900 rpms, which is high. He spent a lot of hours checking things and figured out the car would only surge wit the IAC plugged in. We both check the voltage to all sensors and replaced a few of them including the IAC. The throttle body was worn out so we replaced that.
Literally everything we could think of was checked at least 4 times and we cant figure this one out. The car drives great otherwise. Does anyone have ANY ideas about why the car idles better with the IAC unplugged? The voltage measures perfect on the wires to the sensor.
The car was only surging at a stop and would drop down to 300 rpms and surge up to 900. He fixed that problem but not completely. Upon start up it surges for a couple seconds then levels out although he had to set the idle to 900 rpms, which is high. He spent a lot of hours checking things and figured out the car would only surge wit the IAC plugged in. We both check the voltage to all sensors and replaced a few of them including the IAC. The throttle body was worn out so we replaced that.
Literally everything we could think of was checked at least 4 times and we cant figure this one out. The car drives great otherwise. Does anyone have ANY ideas about why the car idles better with the IAC unplugged? The voltage measures perfect on the wires to the sensor.