I'd bet on your coolant if its hitting temps as low as over here in michigan. I had to get my jump pack out to start my loaner truck, 98 ram 1500 5.2l. The guy ran 50/50 and when I pulled the cap off the radiator is felt like that slime stuff that used to be in the commercials as a kids toy. It was a good -20 out, I think I crushed my balls when I leaned my chest on the fender to jump the frozen battery. Edit: Didn't see your last post. It may be that their gas was gelling up. Wouldn't be the first time a gas station has pumped bad gas. The Shell stations around me are known for not properly changing over to winter fuel, as a result if we get a bad cold snap early in the year, or you go to a station that doesn't get a lot of traffic, and you're in for trouble. None of the marathons or stations they own have a problem though.