V8V Intermittent Hot Start Issue

[DK570]

As the title says, I have a 2011 V8 Vantage that *sometimes* has a hot start issue. Cold starts after sitting for a long time haven't been an issue. However, sometimes when hot it'll rev to maybe 1,000-1,500 rpm at start and then immediately die. It's annoying to not start on the 1st attempt, but its really really annoying when it doesn't start on the 2nd, and the 3rd, or the 4th attempt. Also, sometimes in parking maneuvers it will die. At first I thought since this is a new car to me that maybe I was stalling it, but for sure I've had it die with the clutch all the way to the floor while parking. Otherwise it seems to drive fine. After a few failed attempts to start it will throw a check engine light. It doesn't always do it in the same way, but the most common code is P2111

Previous owner thought it was the key module in the dash, I replaced that, didn't change anything. Redpants was having a sale, so at the same time I bought and replaced the clutch position switch and the ambient air temperature sensor. Still has the problem. I've also cleaned the throttle body and the MAF sensors, as well as run through a bottle of injector cleaner. I'm thinking it's either throttle or fuel related. I plotted the throttle response on my code reader, I also plotted the throttle response on a 2017 Jeep Wrangler JK 3.6l V6, and a 2022 Jeep Grand Cherokee WL 5.7l V8 to compare. When I look at plot on the Aston there is a weird blip at the end. Like the throttle closed too much and then it needed to open a little to be in the correct position? Any thoughts??

I'd like to share videos of the throttle position graphs from my scanner, but am not sure how to on this forum. Is it possible to attach videos here? Or do I need to upload to youtube and share the link?

[Manners79]

There is a known stalling issue caused by the fuel tank especially when less than half full. Cant recall the details but it’s been discussed here before. Not sure if that could also affect hot starting? Good luck with the fix

[DK570]

Manners79 said:

There is a known stalling issue caused by the fuel tank especially when less than half full. Cant recall the details but it s been discussed here before. Not sure if that could also affect hot starting? Good luck with the fix

I've read about that, this seems to be a different issue. It's definitely not related to gas tank level, though I'm not ruling out an issue with the fuel pump.

[DK570]

Well I never got an answer on if it's possible to embed videos here, but I did upload to youtube.

This is the throttle graph from my Aston. There seems to be a weird little opening adjustment at the end. All I did was gas pedal down, hold for a moment and then release.
youtube.com/shorts/4qKn3j3t0Ak

To compare here is a Grand Cherokee (for some reason I didn't hold open)
youtube.com/shorts/PHrLa5on7jo

And here is a Wrangler (for some reason my scanner would only plot here if the engine was running)
youtube.com/shorts/ywjowNbt9Zw

[DK570]

I checked fuel pressure today during a cold start (remember it's January in Wisconsin, so won't be able to drive it and get hot start for a while).  Fuel pressure started at basically 0, climbed to 55 psi while running, and then dropped down to basically 0 again after shut down.  That's probably not good.  There seems to be some disagreement between Redpants and Bamford Rose as to what is normal, but both agree that quickly going to 0 psi is not good.  Bamford Rose says that a drop that quick after shut down will trigger a CEL, but I've not had a light unless it fails to start a few times, and never the code that they say should be expected for low fuel pressure.         
https://www.youtube.com/watch?v=qa9cEqWu_l4

[kabman]

There is a non-return valve in the fuel pump module that maintains pressure in the fuel rail when the pump is not running. You should see a minimum of
apbout 40psi after the engine has been turned off and it should remain constant - not decay to zero.

When the ignition is turned back on the pump primes the system for one second and you should see >55psi. With the engine running it should be a constant 55psi..