you need to be more specific.

It does it not do it everytime!
what the heck is that? did you mean, it doesent do it everytime?

you shoud be giving it gas to take off an if you are and its still droping off you need to look at your iacv, fast idle, or tps. i would say the tps is acting screwy but you would have to hook it up to a scanner an look at the data.