if you are absolutly 100% sure everything is correct then we can simply change the idle stategy, no big deal there. Sometimes the difference in manifold depression can effect the load sites referenced at idle.

but you need to be sure its not any other fault, otherwise if you cure the fault at a later date, you will have the opposite problem.

9 times out of 10 there is a fault somewhere.

alternativly get in it to us and we can do whats needed.