We just added missed fuel-ups for odometer trackers.
We've had a good number of requests for the ability to let Fuelly know you've missed an entry between your last fuel-up and adding a new fuel-up to the site. Now you can check the "I missed a fuel-up" option when you fuel-up which will tell Fuelly to skip the miles/mpg calculation on this round and start up with next one. Here's a bit more info.
You can go back and edit any existing fuel-ups and check the option for more accurate statistics. As always post here if you find problems with this new feature.