rev problem

[siblinghk]

could anyone tell me what the problem is as my micra(98) rev below 800rpm to 600 rpm when the engine starts , it also rev unstablely in between 800 and 600 rpm when the car is idle. i have checked the induction kit and no air leaks found, but i cant find the PCV Breather hose. is it important to plug back the PCV breather hose onto the induction kit?? is it the cause of unstable rev or something else?? sometime when the car is moving, i heard some whistle from underneath of the car and i think it come from the front part of exhaust pipe which hanging beside the engine oil box. if that part of exhaust has air leaks, will it affect the car ??? please give me some advices ....many thanks indeed.

 

[asdame]

the rev speed looks within haynes spec, mines at 600rpm. if it's varying on it's own, some ppl mentioned before that it could be the throttle body that needed it's internal electronics resoldering.

btw if ur looking from above the engine cover, the PCV breather hose would be plumbed to the pipe thats stickin out the top right of cover (lefthand of car sitting in the drivers seat point of view)
pipe in front would have the hose leading down into the front of the engine block, the PCV is the one behind that one.