Cranks but will not start

Have the car listed above Ecotec. It threw a P0300 code a week ago. It shook bad when stopped, ran fine down the road. If put in neutral it would be a little better. If you put on the A/C it would shut off. The next day it wouldn't start. It would crank but not start. Plugs are about four months old. Just replaced O2 sensor two weeks ago. 1.) Replaced coil pack( plugs are getting spark) 2.) Replaced ignition control module on coil pack 3.) Had starter tested( it's good) 4.) Replaced crankshaft position sensor (don't think it's getting power, when I crank engine, tachometer doesn't move) 5.)Fuel rail is getting fuel (I sprayed starting fluid in throttle body and didn't even try to start) 6.)Fuel pump is pumping 7.) New idle air control valve 8.) New throttle position sensor 9.) Kinda sounded like timing chain, so checked that and it's still on and okay 10.) Checked all fuses and relays 11.) No security light on, still tried to reset security just in case Looked for loose wires and electrical connections. Still won't start, doesn't even try. Could it be the ignition switch, alternator? Any help would be much appreciated, it's my work car and can't afford another one right now. Thank you