What causes the sudden loss of power & pedal non response in VW CADDY 2008?

Question

My VW Caddy, manual stick shift, has a problem that has been going on for almost 8 months.

Some times while driving the vehicle suddenly losses power and the pedal fails to respond. It Gains power again after pressing the clutch, Some times the problem come back immediately, other times it disappears for minutes, hours or even days.
I have changed the pedal, the EGR, the turbo valve, the throttle and few related sensors, checked and reprogrammed the computer but the problem still on. I Please Help.