My 05 mazda rx8 is stalling or turning of when i rev to hard.?

I have a 2005 mazda rx8. When i drive if i dont go very slow untill the rpms get higher (maybe 4-6 thousand) then the car will literally creep across the road or even just shut off on me. This happens as i try to give the car some gas. It seems like the car doesnt recoignize that my foot is pedal to the metal and when my foot is all the way down i will still only be in 1st gear at about 3000 rpms. all this with my foot to the floor. Now if i wait a little bit and start off slow until it is in higher gears and/or higher rpms it does mostly fine. sometimes a lil slow or jerky but nothing compared to if i try and drive fast. ive taken it to manly places but either i get "we cant figure it out" or they fix somthing and the problem persists. Can anyone help me please???? i love my car and dont want to have to sell it away!!!!