Hi.

I'm facing an issue with my 2008 Mustang GT where it randomly stalls out of nowhere. And it refuses to start again unless it's left for 10-15 minutes then I can start it back up with no issues and would run fine.
When it stalls out, the fuel pump does not kick on (I don't hear the fuel pump whine) as well there is no electricity going to the coils. another reason I'm sure the fuel pump does not kick on is that after checking the live data via the OBD fuel rail pressure will keep dropping although the switch is in the ignition turned to ON, But as mentioned after I leave it for a few minutes it would start just fine.
Other times it won't start and would need to leave it for a few minutes again.
I have an o2 sensor code on the PCM but I have replaced it and the code is still coming back. But I doubt this is the issue.
Catalytic converters have been deleted and the car was tuned previously.
I have cleaned the injectors recently, new spark plugs, new fuel filter, throttle has been cleaned, MAF sensor has been cleaned as well.

Any Ideas what might be the issue?

 

When did you first begin to notice the stalling issues? did it just recently start up or has it been going on for awhile? Being as you replaced the spark plugs, fuel filter along with cleaning the throttle body, MAF sensor and fuel injectors, I would suspect the fuel pump as the culprit as the fuel pump would appear to be the reason behind the fuel rail pressure dropping.. That being said, I would recommend taking your vehicle in for servicing and have the fuel and electrical systems diagnosed thoroughly.. Meanwhile, wish you the very best of luck and welcome aboard.

 

This issue happens every now and then.
I would say once every 3-4 weeks.

I've taken it to a mechanic and they stated that the ECU has an issue. But I'm not convinced as there are no any other signs that it might be a bad ECU.

 

Howdy. Welcome to the forums!

How did they say the ECU is an issue? Did they provide 5x8 color glossy photos with the circles and the arrows and a description on the back of each one? Or at least show their homework? Something other than 'ECU, oh well.'?

No? Well... that's fine, and anyway you should do your own test on that to prove it out. Get a shop manual for the car and diagnose it with the proper tools and ensure what it is.

As far as no other signs... well, the ECU drives the fuel pump, and the ECU can have that one issue and otherwise be ok, so they aren't wrong, necessarily.

https://iihs.net/fsm/?d=40&f=Electro...204.6L.pdf&p=8

That's the wiring diagram in question, showing the ECU (nee PCM) wiring to drive the fuel pump as needed. As m05 says it could be the fuel pump, but it's just as easily possible to be the ECU or the inertia switch or even the wiring to the fuel pump itself, and diagnostics thereto should be done (and proven if done by someone else if you have questions.) Oh, it can also be the transfer pipe has fallen off from the passenger 'sender', and finally the wiring overall regarding the fuel pump in some way, including a bad ground somewhere.

Hope that helps, and good luck!

 

In that case, I would either take your car to your nearest Ford dealership and have them hook it up to their diagnostic equipment to run a complete diagnostic test of the fuel and ECM systems or follow Houtex's recommendation by getting a hold of a Mustang shop manual along with doing your own testing by using a hand-hand scanning tool to check for any additional error codes.. Until you figure out a way to have the ECM and fuel systems checked out, your just spinning your wheels, playing a guessing game

 

See if you can find a different PCM for your car on fleebay or at a local boneyard.