2000 GMC sierra wont start?

i drive a 2000 GMC Sierra V6 and i went to go start it this morning and it would not start. it cranks, dash lights come on and everything so i know its not the battery i know its not the fuel pump because i can hear it click. i also checked spark in one plug and had it. i have no idea what else to do! any suggestions will be wonderful to get. sooner the better thanks