Help identifying problem, car runs fine idling.

Make sure your oil level is ok, and also check the oil pressure to see if it's intermittent while pressing the gas. Also check to see if it's smoking.

If all is ok, it may be that the rear 3 spark plugs have not been changed (hard to get to and sometimes people just don't change them.)

If you have intermittent oil pressure readings and it smokes even a bit, pull off the front valve cover and check to see if it's gunked up with what looks like clumps of tar. You cannot just remove oil cap and check because there is a baffle under the cap that keeps you from seeing inside the valve cover.

This is common for this engine because of a bad EGR & Emissions Setup in both Lexus and Toyota Models, but since this is a recent problem, you may be able to fix it before it gets to that point.

If none of this is the issue, I would advise taking it to a mechanic, this engine is not only complex, but there are so many special tools that you have to acquire just to tear it down.