the guys here talked me off the edge after I removed my car from the Battery Tender Plus and received a misfire code from my BlueDriver scanner...after I went through the usual suspects trying to diagnose and finding no issues I rescanned with my BlueDriver and found all was okay...chalked it up to what TheFlash points to and my CTS Sport Wagon has been fine for months since...
Most cars need to relearn idle settings after loss of battery power. Some will stall immediately after initial startup if a power source is not used to maintain computer memory during a battery change, or a pause is not given after ignition on, before cranking. After a good bit of wear and tear is put on the parts, compensatory adjustments are made by the computer to maintain efficient performance characteristics.
When battery power is lost, those calibration adjustments are lost and the PCM defaults to baseline settings which are usually no longer accurate for moderate to high mileage injectors, throttle body, MAF sensor and a generally dirty intake path and valves. All of that affects airflow and fuel needs relative to baseline tune specs which remain at new engine settings.
DI motors are especially sensitive to small air/fuel irregularities and will pop and stutter at startup until they are corrected and the data stored for long term use. This is why I often suggest checking long term fuel trims (LTFT) for engine light problems that appear fuel related. If your fuel supply is constantly on the rich, or lean side, the PCM will adjust baseline LTFT -/+ respectively to offset it and short term fuel trim (STFT) will continue to change rapidly for typical minor fuel variations.
Throttle relearn before startup will not correct the effects of system power disconnect, the PCM must first see the discrepancies and then make adjustments.