I've just noticed that selecting and viewing any one of the last three (8/28, 9/4, 9/11) fuel ups from my fuel up log RSS feed shows the Odometer value as 0.0 while correctly showing the Gallons, Price, and MPG.
This might be related to the fact that I imported those fuel ups incorrectly a few times and had to delete them before reimporting them correctly (or it might not be related to that.)
When exporting, the correct information is there but (different issue) newlines in the notes causes the csv to create multiple lines for one fuel up.
On the RSS feed, Fuelly doesn't show odometer readings in feeds. The only data available in an RSS feed is MPG, date, miles, gallons, notes, and price. However, I found the bug you were talking about: a single fuel-up linked from the RSS feed (and from the recent fuel-ups graph), was showing an odometer reading instead of miles as it should. So I fixed that up. (And sorry to be so precise, I just want to make sure I'm catching the right bug.)
On the export issue: line breaks should be ok. Line breaks are allowed within Excel CSV files as long as they're within a text qualifier. We wrap notes in quotes, so programs should understand what to do with those line breaks.