98 z71 wont start

I have a 98 z71. It was running fine then one morning it wouldnt start. It has 180000 miles on it. Never had any problems till now. I thought it might have jumped time. It is getting fuel and is firing. I tore into it. It hadnt jumped time. I went ahead and replaced the gears and chain. I also replaced crank sensor. Still wont start. I am stumped. Any help will be greatly appreciated.

What's the fuel pressure?

Don't know. I can't find my guage.