Stalls at idle

There's two things to consider. The first is if idle speed is too low. This will happen when the battery is disconnected for some other service. The Engine Computer loses all its stored data. Most of that is relearned as soon as you start driving, without you even noticing, except for "minimum throttle". Until that is relearned, idle speed will be too low, the engine may not start unless the accelerator pedal is held down 1/4", you won't get the nice "idle flare-up" to 1500 rpm at start-up, and it may tend to stall at stop signs. A very specific set of conditions is required for minimum throttle to be relearned. To meet those conditions, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.

If idle speed isn't the problem, fuel pressure may have bled down while the engine was off. Pressure should hold for weeks, but it isn't uncommon for an injector to leak slowly. The fuel pump runs for one second when you turn on the ignition switch, in case that pressure did bleed down a little, but if it dropped to 0 psi, that one second isn't enough time to get it back up for starting. The engine may fire on the fuel that dribbled into the intake manifold from the leaky injector, but since system voltage is low during cranking, the fuel pump runs slower during those few seconds, so fuel pressure may not build up to normal fast enough. The fuel pump resumes running during cranking, then it's runs at full speed after the engine has started. That would result in the engine running fine after the second starting attempt.

The best way to identify low fuel pressure as the cause of the stalling is to connect a fuel pressure gauge, then run the hose under the rear of the hood and clip the gauge under the right wiper arm so you can watch it. If fuel pressure drops significantly over time, the first suspect is a leaking injector. Since that doesn't cause any other problems, one way to prevent the stalling is to turn the ignition switch to "run", then back to "off". Turn it to "run" a second time, then crank the engine. That will give the fuel pump two seconds to run before the injectors start firing, so pressure will build up higher.

I get the impression you're over-thinking this by your comment that sometimes it takes two tries at starting, and sometimes more. That would most likely just be a factor of how long the engine has been off since it was run last. The longer it sits, the more the fuel pressure will bleed down, and the harder it will be to get the engine restarted.

My daily drivers are old Caravans that usually have between 250,000 to 440,000 miles. Because leaking injectors can be so common, I'm in the habit of turning the ignition switch on, waiting to hear the hum of the fuel pump stop, then I crank the engine. The potential fix is way too involved to justify the time and expense for such a minor inconvenience. Also, to put your mind at ease, if you really do have a leaky injector, that has nothing to do with an engine stalling while you're driving, or any other problem. It won't cause any other problem either.

Have her try this: Get in, turn the key to on leave it on for 3-4 seconds, then turn it off and back on. Do this about 3 times. Now see if it starts up when the key is turned the next time.
If this works, which I think it might, you have a bad check valve in the pump. That is letting the fuel pressure fully bleed off and it is taking extra time for it to prime. There are a couple of ways to repair this. One is to replace the pump assembly. The other is to buy an aftermarket check valve that can be installed in the fuel line to hold the pressure.

Okay, that is one of the problems with problems like this, they don't happen all the time. Ask her how long it normally sat between uses, and did it set longer before it acted up this last time. IE: It normally sets a day or two and doesn't have a problem and then it sat a week and had the problem? That might help with the diagnostics.

Okay, that may mean it is actually the fuel pump or it's power circuit as you originally thought. If you can find someone with an oscilloscope you could look at the waveform of the pump motor by tapping into the fuel pump fuse and seeing if it had a dead segment or excessive current draw.

Thanks for the question. Check this link out:

https://www.2carpros.com/pages/about-2carproscom

Use 2CarPros anytime, we are here to help. Please tell a friend.

The TIPM is a - insert your profanity of choice here - they can cause a lot of issues and many are ones that are difficult to repair. However in your case Chrysler has a remote relay kit that puts a new fuel pump relay outside the TIPM. That way the pump turns on and off as it should. The issue with leaving the bypass in is that if there is an accident the pump doesn't turn off with the relay. I believe the same company shows that relay install wiring.
The choice is yours.
Thank you for replying back. It can make it much easier when others have the same problem.

In that case it might be OK. Didn't read all of it because I'm used to just replacing the relay with a better one when I run into a problem. Either way it seems like it works.

It is not something that is fun the first time, but after you do a few it's not difficult. The hardest thing is getting a relay that is better than the OEM that will fit. Normally I will replace the relay, then add a good external relay for the smaller one to power. Takes the load of the pump off the small contacts that way.

You can lay that right at the DaimlerChrysler ownership period, they wanted the same mess on those vehicles as they had on the overly complex German stuff they already built. For a while the TIPMs were being replaced so much that they couldn't keep up and were over 3 months behind. Worse then the fuel pump relay is that the horn relay, each turn signal, Headlights and most other electrical stuff is all in that box. Right front turn signal fails = replace the TIPM, horn stops working = replace the TIPM. Etc.