1992 Buick Century multiple question needing a answer.

Engine Mechanical problem
1992 Buick Century 6 cyl Front Wheel Drive Automatic

I have a 1992 buick century and I am not understanding with having replaced my spark plugs, wires, my car wants to kick over but when I do try to kick it over to start it wants to start but has a sputter like pop as if its going to back fire from the air filter area of the car, I have also come to smell and see a leak with gas mixed with like oders from what looks as if its somehoe mixing with my coolent from the under belly of the bottom of my car, its got me so mad I am about to junk it if I cant solve these issues if there is a solution help me please