So I have already dealt with the 3.0L high idle issues before and they disappeared. Now it is doing it again but only when I have been driving for about 15-20 minutes with the a/c on. When it idles high my a/c does not work. Warm air will start to blow, but if I get the rpms to 4 grand or so it will go back to normal idle and my a/c will kick on. Ive replaced every part that could cause high idle...I thought. So maybe a vacuem leak? Please help with any suggestions you may have.

 

The temp sensor is going bad . If the PCM senses the engine is too hot it will disable the AC compressor.

 

Would that cause the high idle as well?

 

does the air come out of the correct ducts?

when I had my vacuum leak, mine originated from a 4wd solenoid mounted near the vacuum ballast. I know you wouldn't have that, but there were two soft rubber pieces of hose to connect the hard vacuum line to the ballast. did you check/replace those?