I did some (rookie) welding two weeks ago and started the car and it wouldn't stop--the old vacuum leak problem. I tore apart the passenger cabin looking for the vacuum line I thought I had singed while welding. I wasted an hour doing so before I checked the vacuum reading at the black plastic diaphragm in the engine compartment.

Thats when I realized a lot of the rubber fittings that coonect the plastic tubing get hard in frigid weather (15 - 20) and they don't fit as well...and several of them can lead to a big vacuum leak. It had nothing to do with the welding. I forgot that the weather had turned frigid recently.

yep discovered that when it was 30 degrees here in florida and tried to shut the car down. had to do it twice.. scared the crap out of me