It is not the VR6, it is the 2.8L V6. Different engine.
This car is a 2000 with 50,000 on it. It is driven mostly in town, with lots of idleing and stop-and-go in hot weather. It has had the valve cover gaskets replaced twice (lots of oil was disappearing) and the catalytic converters replaced last month. It has tended to use lots of oil. I have used 5/30 Mobil 1, 10/30 Drive Clean, 5/30 and 10/30 Valvoline Synth. I use good filters like K&N, Mobil 1, etc.
When I look in the oil fill cap, I see brown metal, and brown residue comes off on my finger.
I just ran an AutoRX cycle, and a week ago started the rinse cycle with Delo 400 15/40. The factory fill is 5/40, so in my local hot weather a 15/40 should not pose a problem, and the high detergency will not hurt.
An interesting aside: the car has for a while now had a vibrating, even but rough idle while stopped in D that would stop when put in park. I was going to take it in, but after changing the oil to the Delo 15/40, the idle is smooth as butter
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Need more detail?
Nate