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Discussion Starter · #1 ·
I have a 2015 Infiniti Q50 3.7 that continues to stall after starting under very specific circumstances.

I'll take it for a short 5 min drive, turn it off for roughly 45-50 min, drive back home 5 min where it starts with no issues.

Now I'll leave it off for roughly 15 min and start it where it then proceeds to die. A couple months ago the engine would start kind of rough in a scenario like this but still manage to fire up okay. Now it completely dies, but it's able to start on the second attempt.

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Never seems to happens if the car sits off for more than 30 min or more.

New battery installed recently as I thought the issue was related to the 5 year old battery.

Wondering if anyone has any solutions.
 

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Hmmm Fuel pump, or maybe a sticking throttle body would be the first things I'd check.

Start the car in accessory mode can be done by pressing the ignition while your foot is off the brake, you'll need to do it twice and you should hear the fuel pump prime itself and see if you
can replicate the behavior. If it solves the issue then the fuel pump may not be creating enough pressure to continue combustion or one of the sensors went bad and is miss-reporting how much fuel is in the combustion chamber.

If there is no change then I'd start looking to see if the throttle body is opening correctly the VQ37's throttle bodies get pretty nasty after a few years
of build up from the PVC system. Granted it usually presents in the RPMs bouncing around a bit when parked and a slightly rougher idle not starting issues.

Still some throttle body cleaner and a rag and easy to rule out.

If neither of those will probably need to bring the car in for a scan tool to be hooked up so they can see if one of the sensors has gone bad.
 
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My G37x used to do the exact same thing around 80k miles. It turned out to be the throttle bodies. Instead of cleaning them I replaced them with brand new ones and I never had the issues again. Check the throttle bodies.
 

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Setting any DTCs?
 

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Discussion Starter · #5 ·
I'm thinking fuel pump as well. A few months back I noticed a hissing sound coming from under the back seat which led me to believe the pump might be on its way out. But over the last month or so that hissing has completely disappeared. When I do prime the pump a couple times before starting, it starts okay.

I will however check if there are any codes next time and take quick peek at the throttle bodies to see how dirty they are (only 60000km).

Thanks for the insight everyone!
 

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My mom's EX35 did the same thing. Dealer changed the throttle bodies and that fixed it.
 

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I have a 2015 Infiniti Q50 3.7 that continues to stall after starting under very specific circumstances.

I'll take it for a short 5 min drive, turn it off for roughly 45-50 min, drive back home 5 min where it starts with no issues.

Now I'll leave it off for roughly 15 min and start it where it then proceeds to die. A couple months ago the engine would start kind of rough in a scenario like this but still manage to fire up okay. Now it completely dies, but it's able to start on the second attempt.

Streamable Video

Never seems to happens if the car sits off for more than 30 min or more.

New battery installed recently as I thought the issue was related to the 5 year old battery.

Wondering if anyone has any solutions.
I had same issue with mine for about a year. I eventually stumbled across someone mentioning cleaning the throttle bodies on a G37 Forum. I cleaned my throttle bodies and performed the idle relearn procedure and I haven't had any issues since then. Recommend trying it on yours and seeing if that does the trick👌
 
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