My 07 LS460L has a pulsating idle. Approximately 2-300 rpm from 1200 rpm. It has, while in Drive dropped to 4-500 rpm then will recover. Also it has dropped so low that I thought it was going to stall but then it jumped to 1500 rpm fluctuated then recovered. I had it in at Sewell 2 weeks ago and they couldn't find the reason until a week later they said the throttle body was dirty. The tech cleaned it and I still have the same issue. No performance issues just idle? I have two LS430' 01&06 and neither one of them have this issue. The fuel rails were replaced under recall. Thoughts? Anyone else experiencing this?

 

My in Drive not moving idle is 700. The idle is pulsating from 500-800 rpm.