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2000 Legacy stalls on startup in cold weather

10-15-2006, 08:12 AM
I have a 2000 Subaru Legacy GT that runs well, except on startup in the cold weather. It will start, go to high idle, then drop rpms and stall. It usually takes 3-4 times of repeating this procedure before it doesn't drop down too low to stall. When it does recover, the engine will go into high idle and then slowly return to normal idle.

There is an automatic starter in the car, but it doesn't matter if the starter or key is used in cold weather. I also have no problems with either the automatic starter or key in warm weather. There is no electrical load on the system when this happens (AC/Defroster/etc..).

I have taken it to the dealer, and they cannot find a problem. Twice. I've also taken it to a Subaru master mechanic who is a friend and he cannot find the problem. There is no code that comes up when plugged in to the computer as well. The only thing that was replaced was a knock sensor that failed.

We're all stumped. Any thoughts???


10-15-2006, 08:08 PM
You could try hooking up the scanner and reading the data stream when this happens. Maybe it will give you some insite on where to look next..?? MAy lead you to a MAP sensor or a TPS sensor??Try it.

10-15-2006, 09:47 PM

Thanks for the suggestion. I talked with my mechanic today and he was going to research this a bit. I will definitely recommend this idea to him as well. Another mechanic related that it could be a stuck idle pin that freezes up in cold weather and lets the rpms drop too low before it warms and actuates properly.

It's greek to me really. I'm a paramedic, not a mechanic. I understand the concept, but not enough to go in and fix it.

Thanks for the reply!


10-22-2006, 10:24 PM
Check your vacuum hoses for leaks. That would be my first step. Could be the IAC (Idle air controller) as you mentioned

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