XR0027

hi guys, I have a 2003 manual xr6 turbo, standard no mods , last night I noticed as I went to overtake a car , I put it back into 3rd and put the foot down, and it took off but as soon as it hit 3500 4000 ish it just cut out like it was breaking down under load? its drives fine and still boosts but under load its like traction ctrl but the light doesnt flash , I tried some differnt coil packs, new plugs any ideas would be great cheers matt