I’m not sure if this is on here anywhere (I’ve searched a lot) so I thought I’d share.
I had an issue with a real high start up idle of around 2000 rpm that slowly dropped to about 1200. I also had the hanging idle on shifts.
I went through the many suggestions and checklists and have had no luck. The only part I changed was the IAC to a Motorcraft unit, which made zero difference.
I finally found a thread while I was looking through 4eye, that spoke of internal diodes in the new IAC motors interfering with the IAC harness diodes of the early foxes. Apparantly the early IAC motors did not have the diode built in. It said to either cut out the diode in the harness or switch the pins in the connector (reverse the wires). This would allow the internal diode in the new IAC to do the work. I went the switch the pins route in case it didn’t work, instead of cutting up the harness.........but it worked.
She starts up perfect and the rpms drop just like they should when shifting. It felt like I was driving a different car!
If this is old news, sorry, but I had to share in case there’s someone else out there like me still looking for solutions!
I had an issue with a real high start up idle of around 2000 rpm that slowly dropped to about 1200. I also had the hanging idle on shifts.
I went through the many suggestions and checklists and have had no luck. The only part I changed was the IAC to a Motorcraft unit, which made zero difference.
I finally found a thread while I was looking through 4eye, that spoke of internal diodes in the new IAC motors interfering with the IAC harness diodes of the early foxes. Apparantly the early IAC motors did not have the diode built in. It said to either cut out the diode in the harness or switch the pins in the connector (reverse the wires). This would allow the internal diode in the new IAC to do the work. I went the switch the pins route in case it didn’t work, instead of cutting up the harness.........but it worked.
She starts up perfect and the rpms drop just like they should when shifting. It felt like I was driving a different car!
If this is old news, sorry, but I had to share in case there’s someone else out there like me still looking for solutions!
