1) does it do this after is completely warm? like after 5 miles of driving?
2) do you have a CEL on? Ive never seen a cat on one of these smell before setting a p0420 code.
If it only does it after filling as i'd guess youve got an issue with the charcoal canister/evap system. But it wouldnt hurt to go ahead and clean the IACV.

Next time you get gas, leave the gas cap off and see if it starts easier. This will tell you if its somehow vapor locking the gas tank.