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Smoke at altitude with cold engine

Engine

Vehicle Information: Year: 1999; Engine (type, size, modifications): 2.5 liter stock; Total Mileage: 24,000; Transmission: Tiptronic;

The car was sold new in NYC, then moved to CO and sold to me this summer. I live at 7600 ft, and commute down the mountain to Denver at 5300 ft.The car emits white smoke (like cars idleing at stop lights in very cold weather) when started from cold overnight. Not just a puff, but for several minutes, and smells of gas like running rich. My Lexus and Audi work fine without startup smoke at this alitude. When warmed up to even 130 F coolant temp, smoke stops. Normal if sits for 6 hours and restart, but smokes again on startup if left to cold soak cool overnight. I have replaced the MAF sensor to cure old P1123, P1125 codes, with no effect on the smoke. I can watch the OBD-II status on my Palm Pilot. There are no diagnostic codes or pending codes. O2 sensors bothcome into dynamaic closed loop control after about 3 minutes, but still smokes a minute or so past that. Drive 1 mile and it is fine. Is this just a design problem at altitude, or is there something I should try fixing?

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