OK this is the third winter this happened to my "White" SE.
Had to stop short for a light and the motor starts running rough and the exhaust smell was terrible.
Most would say the 02 went out right?
I put a bottle of dry gas in her, next morning start it up and it purrs like a kitten and no smell.
Water is collecting in the fuel system during cold winter months and possibly messing up the regulator pressure I guess.
Thank that crap Winter oxygenated ethanol doused fuel formula we are forced to buy in new england.

You should see what "winter" additive has done to my car....

Acrid exhaust, rough idle, no performance. I'm thinking its the culprit behind my latest troubles (need to replace all 8 injectors)

I can't wait til Feb 15 when they start producing the summer blend. I'll be sure to fill up and get my mileage back.

Hey! Thats the same problem I've been having! New Denso O2, AIT sensor, cleaned the intake... no dice.

What addititive did you use? Heet? Just one bottle?

I had the same problem, EGR valve was sticking. Next time it happens, give the EGR a good hit with a hard object like a scew driver handle. The spring will free up and idle will be back to normal. Then , go ahead and take it off and clean the valve. Problem should be history........

Also, I now run 89 octane in the winter to make up for the ethanol loss.

Used a bottle of cristy dry gas but have used heat in the past. Make sure its oxygen sensor and cat safe. Isopropal blend is the one to get.

Thanks! I'll try that and if that doesn't work then I'll try to pull a spare EGR apart and clean its guts and slap on the car to see what happens... if I can get it apart, that is.