Car problems

I recently purchased a 1992 Buick century with knowledge of the service engine soon light that goes on and off. The car at times will idle high and will ocassionally stall out and sometimes I need to crank the engine too much to start the vehicle. The more I crank the engine the more I smell the fuel odor. I have changed a lot of parts and it is still does not have good power. It sounds sluggish. Can you please help me.