I recently had to rebuild the engine in my 2001 Cherokee... Everything is running great from what I can tell, but I keep smelling gas, especially when I start it up and often when I have the air on...
My gas mileage doesn't seem to be worse (as if it were any good anyways, haha) and I don't see any liquid spots on the ground. Is this just an aspect that comes with breaking in a rebuilt engine or do I have a gas leak somewhere?

 

It can be a small leak around your injectors. That would be my guess. Some time the leak can be so small to find right away.

 

i had a tiny leak on the bottom of gas tank and could smell it from everywhere, but since just rebuilt engine id check injectors like he said ^ have it run and get out and see if it gets wet, like open the throttle up and keep it revving then look around the injectors

 

Start up your Jeep and with it idling take a visual inspection of the entire fuel system. Check everything from the injectors back to the fuel pump. Look at all the lines and try and track it down. You'll find something.

What kind of shape is your exhaust manifold in? From my experience, if your headers are cracked, the smell of the exhaust gasses escaping can almost mimic the smell of gas.

 

^ Especially if you're running rich which is often the case with a cracked exhaust manifold.

 

Could be an evap leak, that will make it smell like gas without causing any problems but it will normally through a code it it is

 

Did the OP ever find a solution? I have a strong smell of gas at startup, and am throwing an EVAP code. Just looking for some feedback as to where to look first. I'm assuming it's the charcoal canister or one of the lines going to it.