Please help with my idle issue (m)

[jbsport01]

I have a 2001 Sport with the 4.0 SOHC. Lately when I am at idle in traffic and turn on the heat I get a idle bounce. I can hear the compressor clicking on and off every few seconds. When the compressor clicks on the idle drops from 750 down to 500 and catches itself and bounces back to 750 until the compressor clicks on and off again. It is really annoying bacause the truck vibrates a bit around 500 and I can feel the bouncing idle. I have a buddy with a 1997 Explorer and his truck will occasionally do the same thing. If the blower (heat/AC) is turned off, the truck idles perfectly. Will replacing the IAC valve fix this issue? Any suggestions?
TIA!
John

 

[seanthenerd]

Sorry I dont have a solution but I have the exact problem and it is very anoying. I have a 97 sport with the 4.0L SOHC and with the fan(heat/AC) off the truck idles like it should as soon as you switch the fan on for either Ac or heat at idle the truck idles like crap. The compressor clicks then revup then down, then it will click again and revup and down and it does not stop. If anyone has any information on what is causing this please let us know.

Thanks in advance
Sean

 

[TPLYNCH]

Try cleaning the IAC first. If that doesn't help, then replace it. Search for How to clean IAC and you'll find thread with instructions and pictures.