Intermittently after warming up and driving, the vehicle stalls

Hello, does it make any difference if you have the air conditioning on or off? The idea that you need to keep your foot on the pedal to keep it running suggests an air issue at idle. Or possibly a dirty Mass Air Flow sensor. If you haven't cleaned it before or had it cleaned ever, it's definitely due for a cleaning. The Mass Air Flow sensor (MAF) has small resistors on a thin wire that is heated up by current flow through it, and the amount of air coming in will change the resistance in that circuit telling the engine computer how much air is coming in. It is mounted on the air Intake tube going to the throttle body. I would recommend cleaning the throttle plates as well. There is a Mass Air Flow spray cleaner you can get at a local auto parts store. Don't use anything else to clean the resistors though, they have a thin coating on them to protect them. But they do get dirty after a while and then the sensor will under report the amount of air coming into the engine and you can have these types of issues. For the throttle plates being cleaned you may want a shop to do this, because usually a scan tool is used to open the throttle plates for cleaning. This is not a cable driven throttle body, the ECM controls the throttle plates and forcing them open to clean them can damage them, and/or they will need the Throttle Relearn procedure done afterwards.
Here are a couple of guides below to help. If you own a scan tool that can read live data, you can check to see what the flow rate of the MAF is in the data display. But I would start by having those 2 components cleaned and see if it helps.

Also, I'm adding a Technical Service Bulletin about the fuel tank, not sure if you have received this in the mail or not, but just so you know about it.

https://www.2carpros.com/articles/mass-air-flow-service

https://www.2carpros.com/articles/throttle-actuator-service

Hello, are you having issues posting a question? I am receiving notifications but not seeing any message from you.

Sorry about the posting issue. Sometimes if you use certain keyboard characters it will not post, this is to avoid spam on the website I believe. But no there's no adjusting for fuel injectors. You just have to relieve fuel pressure. Pull the Fuel Pump Relay and crank the car over, it will probably start and stall as the remaining fuel is burned but crank a few times to make sure there is no fuel pressure and just follow the instructions below.
Are you sure the code was P0402? That is an EGR Excessive Flow code.
If it's actually a P0402 I would take off the EGR valve first and make sure there isn't a piece of carbon holding the valve open.
What type of scan tool are you using to read your codes? If it's just a basic Global OBD2 scan tool, it might not be reading the exact code correctly. Especially Fords.
The last two diagrams are of EGR valves, the first one is vacuum controlled, and the second is electronically controlled. It will be round with a flat six wire connector.

The 1st and 2nd is a picture of an electronic EGR valve, I know that one I posted early wasn't a very good picture, since there are actually 3 different types of EGR valves. I happened to have one laying around. This will give you a better idea of which setup you have. The 3rd and 4th diagrams below show an ESM setup, it is still a vacuum controlled EGR valve, except it has all the control components integrated into one unit.

Hey no worries,, so sorry to hear about your mother, my condolences to you and your family. Ive been through that, I know how bad it is.
For that injector, I have a part number 7T4Z9F593B, that should be the oem. The stalling issue is abit concerning, unless that injector is flooding the cylinder, are you getting a bunch of whitish blue smoke out the exhaust pipe?

The biggest worry with an Injector circuit code like this is if the injector shorted out and there was an excessive amount of current flow to the injector driver in the ecm. So I would definitely check the resistance of the number 4 injector first thing. It should be between 11 and 18 ohms of resistance. Now sometimes the injector resistance will test ok while its at an outside temperature, where the vehicle has not been driven for the day, Some fail when hot and some when cold,

To check the circuit, the best way is with a 12v automotive test light. We use oscilloscopes in the field, but a test light will do. Ill post the wiring diagrams below,
There is one power feed for all 6 injectors, One the Violet/Green wire there should be 12 volts, and if you hook the test light clip to battery positive and back probe the injector connector on the other wire (Yellow/Orange) with the vehicle running it should have a dim flashing on the test light, That is the ecm controlling the ground side of the injector circuit.

You might have to erase the code to do this test because some vehicles will shut down a failed injector circuit to protect the Catalytic Converter. If you check the injector and find the resistance is below 11 ohms, dont run the vehicle anymore with that injector. The low resistance of it can cause too much current flow and it can burn the driver in the ecm. That is the biggest worry in this situation. Hopefully that didnt happen. You'll have to erase the codes after replacing the Injector too.
Disregard the EGR info, since we had the codes mixed up.
The put that Recall backup about the Fuel tank issue. If you have any questions on testing, just ask... Again, really sorry for your loss.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

https://www.2carpros.com/articles/how-to-replace-a-fuel-injector

I would check the resistance of the number 4 fuel injector with it unplugged, and multimeter set on Ohms, The Test light check is very easy to do as well, but the reason the resistance check on the injector is if it shorted out internally, the current flow to the Injector driver inside the engine computer (ECM) could have burned out the driver. It's the main cause of drivers in ECMs being burned out, same goes with ignition coils that short out, too much current flow and the driver gets cooked inside the ECM and the driver will never be able to activate the Injector again. With a resistance of 11 to 18 ohm, with a 12volt circuit, that's less than 1amp of current driving that Injector. I'd would not like to see you replace the injector and still have a failed number 4 fuel injector circuit.
The test sounds more difficult than it is, and it actually takes about 5 minutes.
Since the ECM pulses the negative (ground) wire of the fuel injector to control it, all you need to do is have a test light hooked to battery positive and touch the pin on the fuel injector plug and the test light will have a dim flash to it. You're just using the test light as a substitute instead of the injector. The guide below is very simple to follow.
This is a circuit code, not a cylinder number 4 misfire code, that's why I'd recommend the testing. The ECM is detecting something electrical wrong with the circuit.
If you're really too uncomfortable doing the testing I understand. But don't replace all 6 injectors, just do the number 4 first. After replacing the injector, you will need to erase the code because the ECM may have shut down that circuit due to the fault.
And if in the worst-case scenario, the code comes back after the injector replacement, then the ECM control circuit needs to be checked, so keep the bad injector just in case.
One last thing, if the injectors from Ford are not too expensive, you should get a Ford injector. Aftermarket injectors from AutoZone, advanced auto, etc., places, can have a different flow rate than the OEM (stock) injectors. They almost always do.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector