For all you Lexus owners out there..
I can reiterate what I've stated in other threads. Spark Plug Gap!
Do not believe all you read in terms of spark plugs and the lack of gapping new out of the box. Half of the plugs are not gapped correctly from the factory. This is a fact and each plug needs to be checked for proper gap.
To add to this, .044 gap IS NOT optimal for your vehicle.. As a matter of fact .046 to .048 is optimal for my GS 350 and may be quite different for your GS.
Gapping at .044 is a starting point for every Lexus. The factory gap is based on a number of instances and conditions. This is based on location, altitude, humidity and many other factors as an average only.
Case in point, my GS shift points seemed off, engine and trans seemed out of sync. I had a trans flush performed (BG Machine), certainly this helped, however, did not clear the issue.
I removed all plugs and re-gapped to .046 to .047. This fixed the issue, Idle has improved, shift points are where they should be and perhaps the car pulls a bit harder, as it should.
Gapping at .044 is a good start, but I wouldn't set that as your defacto.