My 2005 3.0 Alpharetta front end skips under hard acceleration but is fine under normal acceleration?

It's probably axle tramp, most of these things don't have traction/stability control so you push 220hp through the front end of something like an Alphard harshly, it's somewhat to be expected.

It only happens if for instance someone lets you out of a turning or a gap in traffic and have to be quick 

1 hour ago, Westbury boy said:

It only happens if for instance someone lets you out of a turning or a gap in traffic and have to be quick 

 

Load shift.

 

The quicker, and more suddenly, you accelerate the more loading shifts (load transfer) to the rear axle/wheels.

As the vehicle is a fixed weight, less loading will be on the front axles, causing less adhesion. 

 

Is the rear end suspension in prime condition ?

 

Similarly, if your front suspension is less than optimal that will increase the tendency to 'tramp', as Paul described.

 

You should get your suspension checked, when is your next MOT ?

 

The quick, easy and inexpensive solution is to 'take' it easy.

Thanks guys after the first time I now always take it easy on the gas  just booked it in for a. Heck anyway cheers