flat spot 406 2.0L glx

[duntoco]

hi im a newbie and currently have a problem with my 406 it has a flat spot at about 800/900 revs and sometimes stalls when attempting to pull away at traffic lights etc but is fine once it gets over 1000 revs have changed the throttle body and all sensors including lambda sensor and the ignition and plugs and i have run out of ideas please help!!!