Originally Posted by Gary Lewis

AOD tranny. Since it sat for over 3 years you have varnish or somesuch in the passages. I had a similar problem on a C6 and cured it by putting half a bottle of Sea Foam Transmission stuff in it - and then drove it, and drove it, and drove it. Took about 500 miles to completely straighten out.

As for the engine, you are back to doing the "please tell me the answer without any clues" thing again. In order to discuss power we need to know what gear ratio you have, what tires you are running, and what's been done to the engine. Further, you will need to pull the codes from your computer as it'll tell you if anything is wrong. Here are a couple of links on that: Pull Codes 1
Pull Codes 2

I'm sorry if I sound gruff, but you don't seem to get it very quickly. We want to help you, but we cannot give you decent answers without understanding the problem. Please do not ask another question without giving us the detail. And it would be highly preferable if you would give us the results of pulling the codes in your very next post.