Help, any advice will be good, mustang cranks but dosent fire up

Crank with no start troubleshooting

Clean the MAF. Use only cleaner designed for the job. No brake clean. No carb/choke cleaner.

Check for any vacuum leaks. Even a tiny leak will cause problems. Do not cut corners here.

Check all fuses in the engine bay and driver's kick panel.

Turn the key to on but do not crank. Does the theft light go out after a 3 second "prove out"? If not, STOP and find out why.

Does the theft light come on during cranking? If so, STOP and find out why.

Cycle the key on/pause/off several times without cranking. Listen for the fuel pump to run each time. Does this improve starting? If so, suspect fuel pressure leak down from a leaky injector, fuel pump check valve, or pressure regulator (return system).

Use and ODB2 scanner to montor RPM's during cranking. Does the RPM's change? If not, the CKP sensor is bad and the car will NEVER start.
Hold the throttle half way open during cranking. Does this improve starting? If so, suspect a bad IAC.

Does the check engine light come on during cranking? If so, suspect a bad CKP or bad CMP sensor.

Use a set of "noid" style test lights to confirm PCM firing pulse for the ingnition and fuel injectors.