The driver may notice fuel odor, drivability concerns such as hesitation, misfire, stalling, rough running, or difficulty in starting and the 'check engine' light may be illuminated. If the amount of fuel flowing into the breather pipe reaches the vapor canister and exceeds its capacity, the excess fuel may be discharged onto the ground. Fuel leakage in the presence of an ignition source could result in a fire.
Some sport utility vehicles may have fuel tanks that contain an internal breather pipe that was not made to specification. This could result in excessive swelling and cracking of a grommet and subsequent detachment of the breather pipe from a connector tube. When the fuel level in the tank is above the level of the detached joint, fuel may then enter the breather pipe.