I was running Bio Diesel this fall, a cold snap -10 degrees while I was in Grand Forks, ND area. While I was taking it out on the road to keep up with my daughter, it went into limp mode 65 mph and went down to 35 before foot feed would respond. Getting to Grand Forks, topped off with #1 Diesel and put in 4 oz of antigel. It took about 6-7 miles before I could get out of limp mode. Several days later I was in Brainerd, MN and the engine light came on. I have on star diagnostics. They told me the light was from the fuel system, it was not an emergency so I could drive it until I wanted to go to a dealer.
Three days later the light went out on it's own. The next week I put in a new filter as I am sure some of the biodiesel was waxed in the filter. No more problem after that.
I don't totally rely on the on star diagnostics, but when an engine light comes on it did help me! When I went to a dealer who had no time to get me into the shop, he cleaned (my clean) fuel cap and said I could come in the next day. Travelling back to Grand Forks, I did not go back the dealer in Brainerd, MN.