Drcoffee

It could be that some of the bits breaking off the planetary gear locked a valve open.  Flushing the fluid cleared it.  Consider installing a magnefine inline filter to catch future particles from getting to the valves again.

You need to check your pressures, high and low. It could be low on refrigerant.  

remove the valve cover and see if a bolt is bouncing around in there.  As noted below, could be valve lifters.  These engine are prone to sludge.  I certainly would not ignore it.  Have you checked your oil level lately?

So on high mileage rx300 the valve cover gets gummed up and starts to suck oil up into the pcv valve.  Why? When they designed the baffle inside the valve cover, they coated it with a gray material like bedliner.  I have no idea why.  Over time the coating swells and breaks free, blocking the oils ability to drain out of the baffle.  The oil is effectly suck up like a straw in a glass.  The fix is to replace the rear valve cover.  A newly designed version is available now or you can buy a used one on ebay from a 2004 or newer rx330. The defective valve cover is on 99-2003 rx300.

http://www.clublexus.com/forums/rx-1st-gen-1999-2003/582802-reengineered-rear-valve-cover-6.html

If you simply want the headlights to turn off when you exit the truck, leave them in the on position.  They will turn off when you lock the doors.  Its a power saver feature.

Check the altinator.

I am getting a slight shake between 70-80 mph and steering wheel wobble.  I am leaning towards the axle half shafts on the front.  If its happening under load, on the gas, its definitely a cv joint.  You may hear clicking too.  These are easy to replace.  If you mechanic is talking about the driveshaft to the rear wheels thats not the problem.  

What I noticed on my rx300 was that after a 75 mile highway run, I put my hand on the hub of the wheels and all were warm, not hot.  But after driving in local traffic for 1/2 hour and rechecking the wheels, my passenger front wheel was hot enough that I couldnt keep my hand on it.  The drivers side was warm.  So if it was bearing, it would have been hot from the highway drive and if it were the brakes, the calipers would have been hot too, and they were cool.  I can assume at this point that the passenger halfshaft is failing.  Combined with the inner joint grease slung up in the wheelwell, I believe I found my problem.  Hopefully this will help others diagnose there vehicles.

Believe it or not, the MAF affects the tranny shifting.  I had the same issue on my is300. Cleaning helped a little but replacing it fixed the shifting issues.  Rockauto has Denso parts for way less than the dealerships

I just wanted time chime in here. I just removed mine to fix the handle and a couple of the nuts were rusted on and spun in the plastic garnish.  Just pull it off..  It had no effect on the garnish.  You never pull on the ends and the latch has two bolts which carry the weight when you lift the door.  

Also, if you are replacing it because it no longer resets, it can be cleaned and re-used.  Just clean the crud off the spring and axle.  I used non-chlorinated brake cleaner on the metal parts, then re-lubed with silicone spray.  Works like new again.