it shouldn't.

when you remove the battery, your ECU holds a temporary charge, so it wouldn't reset.

give this a shot, disconnect the battery, look for a "radio" fuse in your car, and pull that. in 5 min, reconnect the battery and fuse.

start your car and let it idle for another 4 min. drive around the block normally and put it in park. see how the idle is then.

^ (instructions on how to reset your ECU)