We had a high of 0 today, that was at 1 AM. It went downhill from there. When DD left for work (she has a 1990 S10 Blazer), it was -9, then when she was ready to come home it was -11. Her vehicle cranks and sounds like it's trying to start but doesn't. DH went out with jumper cables and starting fluid, but still no start. She also told me that it's really down on power (I think that started a week or so ago). She was going up a hill (this is ND, the hills aren't that steep) and could only get up to 30 mph. I guess it has been idling rough too. My theory is possible EGR valve problem. I was thinking that maybe moisture in the exhaust caused it to freeze up and it could be partially clogged too? Does anyone have any other ideas? We are thinking of looking at it in the morning when we take her to work, at the least I'll take a paper clip and see if I can pull a code. It's going to be around -21 when we take her in so I don't know how much I'll do then, might wait until it warms up in the afternoon. At 3 PM it's supposed to go up to -1. Any thoughts are appreciated!