Smiley
I apologize if anyone has seen this on another forum--i posted elsewhere initially and did not get much of a response...

I use my GT3 as a DD and heck, i even enjoy driving it to the ski slopes. In any case, many around north america are aware of the recent chill. Recently, while driving to the slopes, the throttle would occasionally ... hiccup. It felt as though there was a momentary decrease in power: it could be felt and heard in terms of engine/exhaust note. It would happen most often going up-hill. Temperatures were around 0 F (i.e. -17 C).

Incidentally, i felt something similar when i drove the car to Colorado in the summer. I wound feel this periodically at high altitudes, just assumed it was a sensitive, highly tuned engine, nothing big. Well, until i was hammering the car through some (lovely) mountain roads (FYI: the road between Estes Park and Neatherland is one my favorites in the country) and the throttle just gave out: no throttle response at all (the engine stayed at idle) and the check engine light turned on. Well, i coasted about 1000' vertical. Stopped, took several breaths, turned off the car...after realizing that i was out of cell service, i took several more breaths and restarted. Well, the check engine light remained, but i was able to drive it (normal response) down to Boulder. The good folks at Boulder porsche, as it turns out, have had several local GT3's do something similar, diagnosed it right away, and re-flashed the ECU. Apparently something to do with the O2-fuel mixture around 8000-9000' (~2500 m) under load. 

Just curious if others have had a similar experience and any good input. ECU problem, fuel pump, some other thoughts. thanks in advance.

Addendum to original question: though this initially occurred several week back, i have felt something similar yesterday morning as i was driving back home. The air temperature was about 15F (~ -10C). the throttle seemed to hiccup momentarily for lack of a better description. Description of circumstances: cruising in a straight line, level surface, about 3500-4000 rpm and only minimal throttle. Though it may be a temperature-independent, other than the situation(s) described at high altitude and feeling this in really cold weather, i have not felt anything like this at any other time. 

Again, thanks.