Sudden loss of Power in my 07 GT
 

I am experiencing a loss of power above 4000 rpm above in 3rd and 4th gear. The car has not thrown any codes, I cleaned the MAFS and it is still there. Car ran incredible for the first 3500 miles. I took to the Ford dealer today and they say that tey can not find anything and he won't let his tech drive it 90 mph to diagnose. He also said he called Ford and they knew of nothing. He said the rev limiter must be kicking in, which I know is not right. ALL I KNOW IS THE CAR WAS A BEAR AND KNOW IT FALLS FLAT ON IT'S FACE ABOVE 4000 RPM IN 3rd and 4th GEAR. IT DOES NOT DO IT IN 1st or 2nd GEAR. ANY IDEAS? PLEASE HELP!!:( :(

Are you running any power adders? You may be running lean and therefore starving the motor for fuel in the upper revs, although it should be doing it in 1st and second if that were the case.

I dunno, I'd take it to a shop like Nicks or somewhere with a dyno and have them run a diagnostic on it....its gotta be a computer problem of some kind, it doesn't sound like a trans problem to me....If it were you'd likely either get 3rd and 4th or you wouldn't, it wouldn't just get tired after 4K.