Note: make sure that the battery is fully charged. I have seen it more than once a car will turn over apparently fast enough to start but fires immediatly once the battery is jumped/replaced.
Double check all fuses. Suggesting pulling each fuse and testing with an Ohm meter.
Confirm the grounding strap between the motor (left motor mount) and the car frame.
Confirm that the fuel pump will run for a few seconds when the key is cycled on/off. Try cycling on/off the key several times without starting. Report if this improves the starting.
Confirm the fuel pressure at the fuel rail test valve. Consider spraying a small amount of starting fluid in the intake (very small amount. This is very risky for modern cars esp SC cars).
Confirm if starting is improved if the throttle is held half way open during cranking.
How have you confirmed spark and fuel? Explain.
Try disconnecting the MAF. Does this improve the starting?
Note: there are relativity few items that will cause a NO-START. Many more sensors are needed to RUN.
Think FAST (fuel, air, spark, timing). The fuel injectors can be tested with a noid light. Confirm spark (method of your choice). If the spark and fuel injectors are firing, the crank shaft position sensors has to be good.
Once fuel pressure is confirmed, then move on to air. The test is cracking open the throttle during cranking.
Now timing. Things that can affect timing include spark plugs wires on the wrong cylinders. Timing chains (broken, skipped teeth). Bent valves. Base engine timing can be tested with a cranking compression test.
Has any recent work been done? Do you hear the normal chug-chug sound during cranking?
