i have a 05 f150 5.4L with 219000 kms (136000 miles). when i hit the gas to pass or just to hammer it at high RPM the engine light will flash and the engine doesnt sound good and it feels like there should be more power. and ideas what it might be

 

I am assuming that the CEL goes off when engine goes back into lower RPM? You need to get the code that the CEL is throwing. After you get the code do a Google search and you should get what the code means and possible fixes for the problem.