Rendezvous 02 won't start, help please
 

Hey all, new to this forum,... I have an 02 Rendezvous it has been sitting for a few years now... Long story short, I've been trying to get it running again,.. I had it running just a few days ago but it was clacking like something under the air intake was loose,.. so I pulled the intake and rocker covers... Found a bad rocker.. replaced the rockers.... Put it back together and now it will not start... I know my fuel pump is working ( just replaced it) I know I'm getting spark... ( Just bought a tester for that) I know I'm getting fuel to the fuel rails.... I'm pretty sure my fuel injectors are firing... ( I'm not sure about that part) I can get it to fire up and run for a few seconds with some starting fluid... But I'm running out of ideas.... Any help would be great appreciated... Thank you in advance.