Gas leak

The leak has nothing to do with tune up, unless I misunderstood. You probably have a fuel tank or sending unit leaking at the top of the tank. The fuel dries before it hits the ground.

I have a 97 Escort, same as 97 Tracer only different lights but both is made by Ford. I do not know if the problem is the same as yours. I notice gas leak beside the tire on the side of the fuel door. You will notice it more when you have 3/4 of gas by doing this step. While driving around 25 mph, step on the gas and then brake and then gas and then brake again for few times. Just to shake the gas tank. I saw the answer to my problem. There is a rubber hose between the gas filler pipe and the gas tank. Follow the pipe from the fuel door going to the gas tank. There should be a rubber hose between them. Mine has a small crack on the rubber hose and that is where the leak is coming from. Hose is $22 at the dealer. If this is your problem. Be careful changing it, extremely flammable. Wait till your gas tank is almost empty. Then, remove the battery cable from the battery(either negative or positive side). Then, before inserting the new rubber hose, put a little grease around the outer ends of the filler pipe and the gas tank pipe and also a little grease inside the mouth on the ends of the rubber hose so as to insert the rubber hose smoothly. Make sure the hose when inserted is fully stretched. No crease nor bended. Then, tighten the hose clamps.