Excessive use of CPU

Hello guys and girls, I have a problem with a method (new), it is
using 100% of CPU for 15/20 seconds. Follow the method below:
http://pastie.org/537568
## kits_controller.rb
def new
  @page_title = 'Add a Kit'
  @kit = Kit.new
  @num_itens = 16
  @kit_inclusions = Array.new
  @num_itens.times { @kit_inclusions.push(KitInclusion.new) }
    render :action => 'form'
end
def new_do
  kit = Kit.new(params[:form])
  if kit.save
    params[:kit_inclusions].each do |ki|
      next if ki[:product_id].empty?
      kit_inclusion = KitInclusion.new(ki)
      kit_inclusion.kit_id = kit.id
      kit_inclusion.save
    end
    flash[:notice] = 'Kit added!'
    redirect_to :action => 'index'
  else
    flash[:notice] = kit.errors.full_messages.map {|fm| "<li>#{fm}</

"}

    redirect_to :action => 'new'
  end
end
## form.hmtl.erb
<% form_for :form, @kit, :url => { :action => action_do } do |f| -%>
    <% @num_itens.times do |t| -%>
        <% fields_for "kit_inclusions[]", @kit_inclusions[t] do |i| -
%>
            <li><label><strong>Product <%= t + 1 %>:</strong></label><
%=
i.collection_select "product_id", Product.all(:conditions =>
{:available => true}, :order => "category_id, model
ASC"), :id, :display_for_select, {:include_blank => 'Select...'},
{:onchange => "qntDefault(\'quantity_#{t}\');"} %><%= i.text_field
"quantity", {:onkeydown => "return noLetters(event);", :class =>
'quantity', :id => "quantity_#{t}"} %></li>
        <% end -%>
    <% end -%>
    <%= image_submit_tag 'btn_save.png' %></div>
    <%= f.hidden_field :id %>
<% end -%>