Crank but no start-- please help

Check for vacuum leaks. Clean the MAF. Use only a product designed for the job. No brake clean. No carb/choke cleaner.

Turn the key to run (do not crank). Confirm that the theft light goes out after a 3 second "prove out". Confirm that the theft light does not blink during cranking.

Next cycle the key off/on/pause (do not crank) several times. LISTEN for the fuel pump to prime each time. Do you hear the FP run? Does this improve starting? If so, suspect a fuel pressure leak down or a bad fuel pump.

Also, on a FI car, parking on an incline will NOT make a difference. Why? Because the lines are supposed to remain presurized while the car is off. Parking on an incline could make re-pressurizing the system more difficult if the fuel pump pick up has been uncovered. But a small amount of fuel is supposed to remain in the fuel pump basket. So unless you have modified the basket by drilling holes, there should be enough fuel in the basket for the car to start.

Next, hold the throttle half way open during cranking. Does this improve starting? If so, suspect a bad IAC.

Last, disconnect the MAF. Does this improve starting?

If asked to guess, I lean towards fuel pressure leak down from the fuel injectors, fuel pressure sensor, damper, or bad fuel pump check valve. Note, the check value is serviced with the fuel pump itself.

The 96-98 MY PATS disables the starter. This give a no crank symptom.
The 99-04 MY PATS disable fuel and spark. This gives a crank with no start symptom.

The blinking PATS light means that the anti-theft system has been activated.

First try resetting by unlocking the driver's door or using the remote FOB.

Also removed everything from the key and try with just the key. Sometimes metal objects can interfere with the PATS signal.

Do you have a spare key to try? You are aware that the key does have to be programmed before use?

For some MY's, the light will display a blink code. Also research on how to active the cluster diagnostic mode.

Review the following information esp post #10.
http://www.stangnet.com/mustang-forums/825922-96-gt-theft-pcm-question.html

http://www.stangnet.com/images/stories/docs/sn95_TSBs/01-06-02.pdf

How to test fuel pump 96-04 MY

If the theft light goes out after the 3 second "prove out" and it does NOT come on during cranking, this is NOT a PATS problem.

If you want further proof this isn't a PATS problem, test for spark. Or spray a small amount of starting fluid in the intake throttle body and see if it "hits".

Assuming that you have checked all of the fuses in the engine bay and driver's kick panel, review the following thread. It contains DETAILED information on how to confirm the diagnosis of a bad fuel pump on a 99-04 MY.

http://www.stangnet.com/mustang-forums/824672-fuel-delivery-issues.html

How to troubleshoot PATS 99-04 MY

Try reseting with the key FOB or by unlocking the driver's door.

Take everything off of the key ring and try with just the key.

The links have instructions on how to access the cluster diagnostic mode. Post the codes and descriptions.

As to how to bypass, dealer, locksmith, or hand held tuner.

Check out
http://www.stangnet.com/images/stories/docs/sn95_TSBs/01-06-02.pdf

01 Bullitt PATS Problem - Ford Mustang Forums

Cluster diagnostics:
http://www.mustangworld.com/ourpics/fcar/dtcodes.htm

In case anyone was wondering if these old forum posts still help they do. Got my 96 mustang running after looking through this forum. The car is older than i am so i appreciate it