is this natural?
Carb'd cars accomplished this with different mechanisms, sometimes idle stepper motors, vaccuum pots etc. to keep the idle up. In the case of an EFI car with IAC like yours, the PCM usually controls that to accomplish this anti-stall.
The 1500 part isn't necessary from a drivability perspective, but may help a less-skilled driver more smoothly shift gears or it may be emissions related. In short, your car sounds fine.





