I so appreciate this Forum! I had the same gasoline odor in the cabin of my 2010 Fit (base model) when the "outside" air was toggled. Took it in to the dealer today and mentioned about the possibility of a loose spark plug. The service rep said there's usually a clicking sound when one is loose, and no click. I was OK with checking possibility of hose leak, so had those tests done. Two hours later, he came back and said "you won't believe what the problem was.." Of course, I replied " a loose spark plug." That was it! The #2 plug, and it also burned the ignition coil as well. He'd never seen anything like this in 26 years, so I hope he passes it along to the rest of the crew. I bet they would have done quite a few more tests, and never would have found it.
So again, many, many thanks for posting this.

 

Interesting!
There seems to be enough stories here that I'd call this issue "not uncommon" - I am surprised more dealer service reps aren't aware of it. Is it the same plug each time too? Hmmmm.

When contacted for a rating follow up to service, I informed the service manager (by email) of the issue, in the hopes that they'll be more aware for the next person. I didn't hear back ....

PS, I never heard any clicking either, but my DD (who uses this car) told me that the shifter would sometimes vibrate more than usual when in neutral at idle.

 

After posting this, I found a Honda Technical Service Bulletin, dated October 2016, that addressed this. Briefly: "a loose spark plug may have not been torqued enough at the factory." 2010 Honda Fit TSBs (Technical Service Bulletins) | HondaProblems.com (also applies to a 2009. others ?)
I called the Service Dept. and the rep will try to get me some type of "goodwill" refund, but not under a "warranty," since my car is 7 years old. I reminded him that there is no way I could have affected the spark plug. He assured me he would do his best, so I have to wait a while on this.

 

Thanks for sharing that. That may explain some of the instances, but not all, because I changed the plugs of my 2008 after 99,000 miles (with torque wrench!), and 43000 later, #2 from the passenger side was discovered to be loose. I tightened plug 2 to the same torque as the others. It will be interesting to see if it re-occurs.

 

I had a exhaust smell in the cabin as well... and then the spark plug on cylinder 2 blew out. This was on my 2012 with 45k miles. Fortunately there was enough thread left...

 

There are plenty of threads on FF discussing loose #2 & #3 plugs producing the gasoline smell and the escaping hot gases disfiguring the coil pack to the point it needs replaced.

It happened to my 2011 around 26K miles.