I have been experiencing slight variations in my idle speeds. The idle can vary from 450 - 750 rpm. It actually slowly moderates in between. In other words, I'm not seeing the low range at one light and the upper range at the next...
Is anyone else experiencing this? It's something that you have to look for as the vehicle is so smooth and quiet, the other senses may not tip you off. I am curious as the vehicle is due for a number of software upgrades and this might be rectified as a result.

 

The vehicle is a 2007 SWB LS460.

 

Bump. Can anyone help?

 

I think this is normal. I noticed the same phenomena on my 460 and now even more on my 600.

 

Thanks a million for the feedback. I have never experienced such a thing with other vehicles, but assume secondary and tertiary systems may draw and cause the peaks and valleys.