replaced faulty eha,hard cold starts,stalled allot,adjusted air fuel ratio,now car does not stall,but it has a loss of power,and it still has ruff cold starts,pops in plenum till fully warmed up,if i disconnect the eha,engine runs so much better and has much more power,do you think i purchased a faulty eha,it was used?why does it run better with no hesitations ,when i unplug the eha?,thanks