1999 blazer wont start

just bought a used 1999 blazer vortec 4.3 engine drove it for 2 weeks .went to start it one day and it wouldnt start , replaced battery , started right up , week later same prob but battery was fine , checked fuel pressure , reads at 61-63 when cranking engine , hold solid at 54 lbs when ignition in on position , removed all plugs im getting gas to plugs and spark .replaced cap , wires also .also replaced  ignition module and camshaft position sensor . after all that it still cranks like a champ but will not start ......at the moment i feel like im burning money , any and i mean any advise would be so appreciated!!!!!! PLEASE HELPhellriaser

Not so sure about the problem, sounds like it is intermittant (because it started when you replaced the battery...for a while anyway) It also sounds like a replacement battery was not the solution but merely a coincidence. There is no doubt that modern cars are extremely complex when it comes to ignition systems, but back to basics can sometimes help. In order to run, an engine needs fuel, spark and air. Sounds like you tested for fuel and spark. Try removing the air filter completely, then start looking for bad O2 sensors and the like. Also try to determine if the spark is a "good Spark" meaning the voltage to the plugs is sufficiant. You may need to consult a service manual for these values. Good luck, I hope this is helpful even if its somewhat vague.