Are you posting an entry on the standard website or Fuelly Mobile at m.fuelly.com? We have a separate site for the iPhone because we know the standard website fuel-up form isn't spectacular on iPhones.
I used to get the sanity check, but it seems to have stopped. The mobile site is fine for adding fuel entries, but it doesn't cover the rest of the site, which I often browse from my phone. I tend not to like mobile versions of sites, as they are often cut down versions, which aren't necessary on iPhones.