Will not start

What is your question?

Just put a timming chain in a week ago run a little rough replaced pug wires cap rotor check to make sure wire was right will only run when hold it to the floor but only will rev up to 1.5 rpm and its really rough and replaced o2 sencer did help much

What makes this problem better or worse?

Nothing i tried

How long has your 1993 GMC C2500 Suburban had this problem?

24 hours