The force is weak on this one. Putting a DC VOM on the alternator does NOT test for a bad diode.
Also requested the results of a specific key cycle test. Don't crank the motor between key cycles. Does the fuel pump run for a few seconds during each key cycle?
With the explanation given about what happens with a cam DTC, the possibility of gas in the oil being part of the problem hasn't been ruled out?
OBTW, on a 99+ Mustang, the fuel pump isn't supposed to run all the time. It is supposed to run for only a few seconds at initial key on and then shut off. The PCM will not restart the fuel pump until the motor has been confirmed running.
OBTW, there are several causes for the symptom of "motor will not take gas". Examples include:
- Vacuum leak
- disconnected fuel pressure intake vacuum reference line
- low fuel pressure
- blocked exhaust
- poor engine vacuum perhaps from a base motor problem.
If this were my car, I would make sure there are no vacuum leaks or exhaust leaks.
It would be handy to "know" the fuel pressure. An external gauge is nice but it also helps to know what the PCM "thinks" is the fuel pressure. An ODB2 scanner is the best way to get this information.
Does holding the throttle half way open during cranking improve starting? If so, consider a bad IAC (black vented) is not allowing starting air to enter.
Does disconnecting the MAF improve starting?
Again, go back and cover the basics before digging into what's wrong. You will thank me in the end.