1995 Chevy Suburban Fuel Smell

It's best to have a gas cap. Look for gas leaks, engine compartment, everywhere. You can check evap hoses, lines. Use a fuel pressure gage, cycle the key to build pressure, turn off, maybe you can find a good place to clamp return line without causing any damage. To See if pressure holds, you need to clamp both the return and supply lines. I have heard of some hoses having a hard plastic insert in them, so you have to be careful about clamping.