A really common problem with the Jazz/fit (I assume it is the same for the Fit) is the bit of plastic string that holds the petrol filler cap to the car breaks.
I have designed a replacement, made from TPU. You can either use the new end or print the collar and that fits inside the plastic clip on the filler flap. It just pulls apart,once it has been slid off the flap.
Make a note of the way the clip fits to the flap as it doesn't go the way you would expect it if you don't make a note..
Just super glue the pieces together..
As with TPU, I printed it slow 40mm/s