I have a 93 Prelude Si (auto transmission). Every now and then (its happened only a couple of times, but my car is only like 3-4 weeks old), when i floor it the RPM's will redline and stop in 2nd gear, it wont shift to 3rd gear and so im stuck going about 45-50 mph until i let off quite a bit... doesnt seem like it should happen... any thoughts or suggestions?

 

If it sticks into second, one of these days it 'll stick for good. You might want to try Trans-X it might help. If not it's time to start looking for another tranny.
Sorry. I hope Trans-X does it for you.