2007 Toyota Camry LE rough idle in the summer with the A/C on

I was wondering if anyone else has had this issue. I spent over 3 years bringing the car to the dealer to try and fix what I felt and still feel is a problem with the car. In the heat of the Phoenix, AZ summer with the A/C on the car has the following occur - when idling in neutral or park the engine RPM goes from 500 to 700 and then back to 500 on a 2 second cycle. The 4 cyl engine does not like 500 and at that RPM the entire engine vibrates quite badly. The car dealer tried to fix the car with the help of the factory technicians to no avail. They once replaced the computer - declared that the problem was fixed and at the first stop light the engine idle issue occurred. After 3 or so years I was told that this was “within factory specifications”. It is disturbing that Toyota would consider this to be acceptable since every time I get to a stop light I think the car is going to die (it never does) in the summer. The dealer once took an identical Camry (same year and engine) and placed my can next to it and admitted my car had the rough idle and the other car did not but they never figured out why. I asked them to send the car off to a factory location when they could connect the computer to a computer harness and determine exactly what the computer is seeing and why - perhaps- the computer is changing the idle. They said that they would not do this. I also expressed concern that this excessive vibration could damage the engine or other parts in the engine compartment and I have had several problems. One fixed under warranty was an A/C leak. My water pump leaked at a relatively early mileage. Now I burn a quart of oil every 1200 miles (which started around 75,000 miles) which is very unusual for a Toyota. Anyway I was wondering if any other Toyota Camry 2007 or later owner has seen the same issue.