Hi,
Any ideas in what this might be? My 2010 LS460 sometimes will not complete the start. Turns over like it should start but doesn't. May do that 2 times and then it starts. Its erratic.

Well, a couple of things come to mind.
Low compression which would be related to engine wear.
And a weak battery which doesn't turn the engine fast enough to develop the necessary compression. Might be a good idea to have your battery tested - sometimes batteries develop internal problems that cause them to be unable to deliver max current. A battery dealer should be able to test your battery.

In addition to this, poor battery terminal connection may cause problem too. Starting problem is always ignition or fuel delivery issues.

Are the spark plugs original?

Yes, 60k on then.

Bad starter relay or some loose connection?

My money is on a weak battery

Battery is in great shape. Has it checked. One year old too. Forgot to mention. There is an Audiovox remote starter installed by previous owner. Today It started on its own.Going to have it removed

Had the previous owners aftermarket remote start removed and problem solved. Bestbuy installer said it wasn't up to his standards.

Thank you for posting this issue.
Our 2010 80k has the same problem. It has only happened 4 times in the last 10k miles
No problem on cold starts. Usually it happens on hot days when you shut the car down and try to restart it in a short period of time.
Of course it has mostly happened when my wife goes shopping. It happened to me only once traveling in New Mexico this summer. I filled up with Shell V power ( first time using V power). I noticed the ethanol rating was 14% at the pump. We headed north at a nice LS cruising speed for a few hours. Outside temp > 90 degree. We grabbed a bite to eat for 45 mins and it happen when we tried to start the car. Ugh. The engine turned over, but no start. Second push of the button engine starts, but runs rough and dies. Third push of the button the engine starts and runs smoothly. The car ran great for the rest of our trip.

Toyota Tech Stream showed no codes prior the trip. After the trip, code P1604 (Start Malfunction) was set. This code doesn't illuminate a dash indicator light. Initial web search on this code showed;

• Low Battery charge
• Starting system
• Low quality fuel
• Clogged Fuel filter
• Faulty Engine Control Module (ECM)

Ah ha, that was pertinent information. When something isn't working properly any related aftermarket add-on becomes the prime suspect.

And I believe 60K is the change interval on a 2010.

If the installer botched the installation. I do it myself.