Slow/check engine Transmission problem?

Yesterday my check engine light turned on, it kept going on and off all day. I first thought the problem was my gas cap which was loose, but after i fixed that it, the light kept reappearing. Today, i realized that my car was extremely slow. When i floor it, it feels like im driving a geo or something. Im thinking that my tranny may be slipping. What are the symptoms of a failing transmission. Thanks

[Earthworm]

Before assuming the transmission, check what the check engine light is trying to tell you.

You can check the codes with help from the SVXipedia.

Ya, i just did that today and its the engine knock sensors, so i gotta get those replaced which is much better than a new tranny. Thanks