99 k3500 7.4 vortec. Smelling gas but no leaks. where is the smell coming from?

 

Vapor line, from tank to motor?

 

 

Vapor line is one of the 3 that come off the top of tank and goes to charcoal canister then to intake manifold,do the sniff test

 

 

One more thing I forgot to mention was. I’ve been smelling the gas odor for some time now. Over the weekend all of a sudden truck starts to misfire as if we’re flooded and idling rough. Put a scanner to it and reading codes “P0172” bank 1 too rich, P0175 bank 2 rich and P0300 misfire. What do you think might have caused this?