I have noticed inconsistent behavior when using the mobile site from my Blackberry Storm 9530. I can open the main page but selecting a car will sometimes not work. When it doesn't work just get an empty white page. Have there been any recent changes to the mobile site, say within the last 3 weeks? That's probably around the time I last used without issue. Based on the main mobile page I feel like something is different. I don't think it looks the same as before and reminds me of a prior version from months ago that had caused me issues (although a different one as before I couldn't select a car).
Aside from this I enjoy what you guys are doing. Keep up the good work!
We launched a new version of Fuelly Mobile in February. The new site is based on jQuery Mobile which updates frequently. So it's possible some changes are happening the background that aren't working out for your particular phone/browser combo. With that in mind we created a "Basic" version of the site that sidesteps jQuery Mobile completely, so you might give that a shot.
Go to Fuelly Mobile and look for the "Basic" link at the bottom of the page. Click that, then the "Home" link on the following page and you should see an extremely basic version of Fuelly Mobile. See if that gives you better results.