I live here in Colorado at 6800 ft. and run an EZ box. Truck smokes pretty good rowing thru the gears. When we took a trip to the Calif coast in '02, I was amazed that the truck didn't smoke at all down there!

Summertime, I have to back the EZ down to #2 pins, as running on #3 pins (wide open) will blacken out an intersection. And no, NO amount of feathering the 'skinny' pedal will cut down on smoke on pin #3, especially with the weight of the slide in camper and cargo trailer in tow. Running #2 pins in the summer makes smoke control a little more manageable. Helps to keep the tree hugging smoke ***** around here placated.