So I recently filled up at a Marathon gas station, pretty much right after the gas light came on (which apparently means that there's an eighth of a tank left in it). Usually it takes about 8.4 gallons to fill it up and it's all good. This time, however, the pump seemed a bit strange and it filled it up to 9.4 gallons, even though I pulled over to get more gas immediately after the light came on.

So, I'm driving around, and I notice that every time I'm at a complete stop, still in D, I feel a rhythmic vibration in my seat. I did some tests and switched gears, and every time I went to either N or R, the vibration rhythm stopped.

To be on the safe side, I decided to drive my fit around town a bit to perhaps burn off some of the extra gas I got. I drove about 36 miles and pulled into the hotel I'm staying at, and I couldn't feel any vibrations in the seat anymore.

So, I'm just worried (after seeing all the things about overfilling gas and damaging charcoal filters and catalytic converters), should I be worried about damage that already occurred? I should mention that a while ago, I noticed one of my muffler hangers broke off and was causing a rattling, but the mechanic moved it out of the way and said that the second muffler hanger would hold it. Would it just be this?

I'm really confused and paranoid, as I've got a two hour drive coming up to get back home, and I'd rather not have a breakdown on the highway.

 

You don't mention mileage, but you may need ignition coil-packs, spark plugs, or a valve adjustment. (It usually pays to do all three)

Often, a very slight miss can be felt as an intermittent vibration at first.

I'd not worry too much about a single instance of over-filling.

+++++++

PS, I'd fix that exhaust hanger. If a manufacturer designed a certain amount of support for the muffler, that is what it needs!

 

"I went to either N or R, the vibration rhythm stopped".
MOTOR MOUNT located under driver's right foot area just showing its age !!
Misfire will be pronounced in BOTH R and D gears.
Bad ignition components are causing brief idle dip when going from N to gear and engine coughing and hiccuping when accelerating in 20 to 40 speed range to pass a slow moving traffic or catch a yellow light. A delay in response during acceleration (acceleration lag) is more related to fuel mixture (or injection timing), not fully closed EGR, bad pistons/rings and restricted exhaust

 

I have not looked at the gas vent system on the Fit but if it is like others I have seen, what you describe sounds like an over fill situation and a flooded / saturated Charcoal canister. If it is saturated, while driving it the canister will eventually purge the excess fuel out of the canister. After that it should run fine.

Do not worry about it for now. If it continues after a few hundred miles then maybe you have a different problem.