I have a 2.2L '98 engine...there are three lines that are fastened by a clip attached to the fuel filter. Two of them obviously are for gas but the third one seems to be part of some sort of vacuum system.

 

It's got a gash in it and I was wondering what it was for and the kinds of problems it could be potentially causing.....

 

Thanks!

 

--Damien

That third line is for the Evap emissions control system. It's thinner than the two fuel lines. You'll probably get a CEL with a code for evap system leak or incorrect purge flow. Fuel vapor from the charcoal canister will leak out of the hose, probably make it smell like gas under the hood, but most likely will not affect overall driveability of the car.