I have/hopefully had the same problem with my 95 ES300 with 119000 mi. I had a Lexus service garage replace a leaky power steering pump, crank seal and cam seals. Also, had my timing belt changed while they had everything torn apart. After all that work ($1500 worth), I began noticing the burnt oil smell again (very strong). While having my transmission flushed by another garage, I had them clean the area where the oil had leaked and check for leaks. They found nothing and so far (1 day) I have smelled nothing. I will be taking my car back to the Lexus service garage for a leak check. Hopefully my problem has gone. I’ll let you know how I make out. I know what your going through…the smell is very strong and frustrating. ;)