That is normal, but three seconds sounds a bit too much. You can get a "sprint booster" which will correct that, but I would not waste the money if you are going to make any additional performance modifications. When you complete the mods you will want to "tune" your car. That will eliminate the throttle lag.
If you are only concerned with the lag and have no desire to mess with anything else under the hood then the sprint booster is the way to go. Have fun, but be careful.