I have a 2003 Chevy cavalier that will not start or even try. It cranks fine, I have verified it has spark, I replaced the plugs and crank shaft position sensor, timing chain is intact, but I didn't verify timing, or a compression check yet. I haven't checked the fuel pressure yet, but can hear the pump prime when the key is turned on and the spark plugs have fuel on them when removed after cranking. I have also checked fire to the injectors with noid light.

Fuel pump, fuel filter, electronic problems, etc. List could go on and on. Find a reputable mechanic

The battery starter and alternator would only affect cranking.
Someone will need to find out if it is spark or fuel related to know which system to inspect.

4 3L 5 3L Chevy Vortec Distributor install

2 things come to my mind. first I would check the fuel pump unit. Usually a bad fuel pump would fail when it gets hot,only to resume working after cooling. To check if the fuel pump is operational when the car dies,put the key in On position right before cranking position and try to listen to the fuel pump making its operating noise or not.u need to be in a quite area to be able to hear it. U could take it to a local mechanic and ask him to check the fuel pressure from the pressure valve in the engine bay. second scenario is the CSPS. Crank shaft position sensor,located on the top side of the transmission near the flywheel housing.(front top side of the transmission) a bad Csps would fail and cause the engine to die when it gets hot even under very normal weather conditions. Check and let us know. Good luck

Definitley NOT an O2 sensor(they don't even do anything for the startup).What happens if you shoot some starting fluid in it?

First check and see if you have spark at the sparkplug, if you do then check the fuel pressure if its not within specs replace fuel pump.

now you must check for fuel delivery. find the shrader valve remove cap push the center as if letting air out of a tire, if there is a sudden burst of fuel then fuel pump is good but if not then check for electricl supply back at the fuel tank,before replacing the fuel pump.

check the throttle position sensor,it may be stuck and it wont start unless its all the way back.Almost like trying to start it with the gas pedal down-which it will crank and crank but it wont start.

crank sensor bad maybe - this is what provides the timing for the ignition system
bad -sensor = no spark every time...
The sensor is on the crank case near the crank pulley.

the problem is the crank shaft position sensor ! I just replaced it on my wifes and it runs like new....