cold weather throttle response

[fve]

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.

[clord]

Hi FVE..... You ask if others have had your experience...... I'm LOL because I had the exact same experience in my '04 GT3 on the exact same road!! I'm in Boulder and was taking a drive in the mountains, showing off my, at that time, new GT3 to my car buddy....He was driving when it did as you describe. After accusing him of breaking my new car, we restarted it and drove down to Boulder. It was a brand new problem at the time. The current lead Porsche tech at Porsche of Boulder (Dave Petitti) was working at Prestige Imports at that time(where I had bought my GT3), and he had, I think, three new GT3's that had experienced that problem. One brand new one was driven to Denver from the west coast and had had it happen several times to him in Utah. Dave worked the issue with the area reps who contacted the factory. Soon, a factory tech flew to the US with a suitcase full of replacement ECUs with updated code in them. My car is still running fine on that replacement ECU from Deutschland. Later the problem was diagnosed to a limited serial number range, and, as Dave told you, an update engine code was distributed and made available to re-flash affected ECUs. It was said that the problem is related to high altitude running, not necessarily cold weather running.

[1999Porsche911]

What was the CEL code?

[fve]

What was the CEL code?

I think that it is equivalent to the OBD code, if so then it was P1266.

[fve]

Hi FVE..... You ask if others have had your experience...... I'm LOL because I had the exact same experience in my '04 GT3 on the exact same road!!

at Porsche of Boulder (Dave Petitti)

It was said that the problem is related to high altitude running, not necessarily cold weather running.

I used to live in CO, now in PA. I still get out there once in a while. It was quite a drive to/from PA. In any case, she (the gt3) was very happy in the mountains otherwise. photo from Brainard lake below (love the hiking).

Yes. Dave was very helpful. i guess that the problem could not have occurred in a better place. ;)

Any other thoughts w/r to the cold since it has only been noted with <20F (<-10C) weather.

thanks fve

[clord]

Yes, it was DME/OBDII Fault Code P1266. Here's my original post on the event: http://www.renntech.org/forums/index.php?s...pic=633&hl=

[clord]

Oh, and to your question.... no, no other issues with cold running. Of course, the stock PS2's do not like very cold pavement, let alone snow.

Enjoy!