My rx-8 is actting up. I push on my gas and it doesnt go anywheres what can this be? I have it at a friends for now but we have no clue what can possibly be wrong with please help!

Have your friend improvise and 'create' an exhaust leak as close to the head as possible (loosen whatever needed but do not remove) just enough to allow exhaust passed , my theory is that one or more converter is melted down and severely restricting the exhaust. It can inhale , but it can't exhale...My guess--- now prove me wrong?? remember just loosen a little , then try running it and see what difference if any in response there is. Maybe reply with results. Good luck......OR electronic throttle control malfunction , which in that case a scan tool would be best to verify which one!