if you reset the ECU then do some quicker throttle take offs, the ECU learns and will provide better response times.
It may be my "want" to make it so but I do it when I begin to feel that delay response and it's fine again until I do too many slow starts.
Do at your own risk - if you have a tune make sure you have a backup on your tuner. I haven't had any issues in doing it but that's my experience - yours may vary.
From Quadratec:
The following procedure will allow you to reset the memory and allow the computer to 're-learn' how to drive by adjusting to the drivers habits and the vehicles modifications.
1. Disconnect the battery by removing the positive battery cable. Remember, the positive battery cable.
2. Ground the positive cable to the negative cable for 30 seconds to erase the electric charge in the capacitors.
3. Reconnect the positive cable to the battery.
4. Turn the key to on but do not start.
5. Turn the headlights on.
6. Turn the headlights off.
7. Turn the key off.
The ECU has now been reset to its factory settings. For the next 50 warm-up periods the ECU will re-learn the engine and driving habits for your driving conditions and the newly installed parts.