When you say you replaced the breather hose, one would have to
imagine that it was the small upper one you did at the back of the
intake manifold. Is this so?
If so, spray some throttle cleaner below that hose and see if idle changes.
If lower breather under intake and fuel rail was not done, then I would start there.
I will be posting procedure for replacing that hose later tonight. Meant to do it Monday,
but didnt have time.

 

THen I would follow what I said and spray the carb cleaner at the back of the intake manifold where that pipe goes into a little breather hose then into another intermediate hose then down to the lower breather. Spray all around there while vehicle idling. See if idle changes.

 

The carb cleaner can tell you a lot. The shops we mail parts to and our own shops seem to go through a lot of intake manifold gaskets as well. The carb cleaner should tell you something there.

Be careful with it and have a fire extinquisher handy. Don't want to start a car-b-que!

 

I will tell you what, just try this, clean the throttle body blade if the lowerbreather hose is fine