I have a 1999 Grand Prix that I replaced the cam sensor, crank sensor and still no spark, what I try next?

Unless you're independently wealthy you need to stop replacing random parts and hoping for the best. Instead you need to figure out the problem and then fix it. It could be a bunch of different things, but from your description it sounds like a failed fuel pump. Turn you key to the run position and see if you can hear the pump start up and run for a few seconds. If you hear nothing then that's likely your problem. You also need to have the trouble codes read to find out what the car thinks is wrong. With that information in hand you have a much better chance of getting it fixed without bankrupting yourself.