Sidekick won't start?

I have a 1994 Suzuki Sidekick with 116,000 miles on it. It has a 16 valve 4cylinder engine with a 3spd auto with overdrive. I replaced the sparkplugs, cylinderhead gasket, and sparkplug wires. When i start it, the engine fires but doesn't start. Sometimes it backfires a little on me.