1994 Chevy Corsica Engine will not start

Engine cranks but does not start and will occasionally backfire through intake. I have checked for spark on all cylinders and it is good. Initially when I checked fuel pressure it was low so I replaced the fuel pump and that corrected the low fuel pressure problem. Still would not start. Checked cam timing and chain was loose so I replaced the timing chain set. Engine still will not start. It is getting fuel, spark and air but not starting and can not figure out. Thinking that it might be camshaft position sensor but was trying to get some advise before replacing any more parts. Also ran a compression test on all cylinders and the range was between 160 and 165 psi with no leakdown. Still the engine cranks with the occasional missfire and no start.