Hello.
My Wifes 2013, 2.4 Terrain SLT (over 120,000 miles) started stalling (most the time dying) at stop lights recently, starting about a month ago. After I drove it a bit, it happens when sitting in first or in neutral, when coming to a stop or when taking off and seems random as sometimes it runs just fine, when I shift back into park, it doesn't do it or hasn't yet.
We recently had the intermediate drive shaft, sway arms replaced by the Dealer with an oil change, and as we just moved to this State, we had an emissions test pass 4 months before this work was completed (its scheduled to go in to the dealer to be looked at in a few days).

It has had every service bulletin completed on it in its past, below are things I have done in order, to try and resolve as its not throwing a code.

Ran injector cleaner 3 or 4 fills ago, changed air filter, cleaned MAF twice & installed new throttle body, installed new spark plugs, new VVT Solenoid Valve Kit (both). -Edit: I also disconnected the battery for 10 mins after installing the new throttle body.
Its not throwing a code or check engine light and in testing, it starts the issue in first gear (no other gear) but can happen in neutral as well, it only does it from time to time but sometimes it can be 3 or 4 times in a row, it will die and after restarting (it restarts no problem) it runs fine until it decides to act this way again.
I am at a loss at what's causing this, any suggestions would be a great help, oil also does not smell like fuel and no emission smells in the cab.

If you barely tap lightly on the gas pedal when it begins to do this, it seems to get a little fuel and save from dying although this doesn't consistently work, if you hit the gas pedal more it will die quickly.
We have had this vehicle for years without issues besides service bulletins and have taken care of it, kind of confused at this point.

PS: I will update this thread if/when the problem is resolved and what it was, any help is appreciated.

 

Aftermarket throttle body by chance? What codes / live data caused you to change it? MAF data, is it under / over reporting? No data? You may have introduced additional faults. More investigation needed.

 

GM Throttle Body.
Me and my wife happen to be on our ways home and she was not too many miles ahead of me and she was at a light while I was on the phone with her when it died again, so we swapped cars when on the highway. It was out of Eco mode and I ran it on the highway slightly hard, this was the first tank of injector cleaner quite a few trips in on that tank, I drove it around 15 more miles.
It never stalled on me but it did throw a code (the only code it has thrown for all this and only that one time), I stopped at auto zone and had it read,

P0506: Idle Control System RPM - Lower Than Expected. (Most likely solution was to clean the throttle body and set Idle adaptation).
Oil level passed, Battery Voltage at the time 12.47 V.

Since I replaced the throttle body, out of Eco, RPM's typically are around 900RPM in park and about 800RPM when in Drive, holding the break.
Before that it was about 700 with 10, 20 RPM bounce out of Eco.

 

All good observations but to isolate the issue you're going to want to view live data. Airflow, fuel trim, O² sensor response and reporting and so on. I'll just suggest a paid for diagnostic then you can decide if you are equipped to perform the repair or need to hand it off. You seem capable. Good luck!