I have a 2008 LR3 with the 4.4 with 87,000 miles. When the truck is not ingear the RPM will be fluctuate between about 400- 700 RPM. Once the truck is ingear it goes away. A/C on or off plays no part. The engine shows no lacking in performance.

 

Could be lots of little things like bad gas, dirty injectors, exhaust leak, IAC, etc...

This where a scan tool / code reader is handy as to pinpoint where to start.

 

Clean your throttle body. That will fix the idle fluctuation, the blade controls idle speed, no IAC, and when it gums up with Carbon, you create an air dam, so it will constantly be adjusting itself due to it's known position not allowing enough air in. Keep in mind though, that there will be just as much build up, actually more, throughout the entire intake system, and the proper repair is a full induction service to clean it all out. Also a good time ti check the PCV for proper functionality.

 

I agree with roverguy7, the same thing happened to mine and I cleaned the throttle body and now my rpms don't fluctuate.

 

Thank you guys for all the help. I just got done cleaning the mass air senorand throttle body and it made a world of difference.

Thanks again

Branden