Hi mate arent cossies fun. 1st i think the lambda does work on idle to give you the closed loop, (im sure ill be corrected if wrong) as this tells the ecu the amount of unburnt fuel then its maybe faulty.
Also double check ya phase sensor and that its timed bang on in line with the mark on the dissy body, remember tdc on bot pulley is the lug and not the mark.
Sure someone else will add something ive missed.
Good luck. Steve