Ford focus intermittent power loss

Hi guys i have a ford focus elle 03 1.6 duretec se and it keeps lossing power after a around 6 mile but will idle spot on as if its goin in limp mode but its not showing any fault codes iv tested tested the fuel pump volts and amps and pressure tested the the fuel system new plugs(gaped to auto datas spec) tested the resistance on the ht leads 4 different coils 2 wer new and others i no works new crank sensor new fuel filter iv even went to the extent of changing the fuel pump pick up gorz and flushing the fuel pipe out with compressed air and still no luck any one with any ideas
Ps if it idles for 5/10 min it starts running rough