Hi im new to the forums, so hope to get some insight. Just bought an evo 9 mr. It's tuned by English racing. The idle is consistent at 1000-1100. With ac on like 1300? But my problem is when I go into neutral the idle surges down to 800 then up to 1300 again. Then fixes itself after 2 surges. Is it normal with a tune? What are your guys opinion ? Thanks

 

Let English check the tune

 

My "stock" evo ix does this. Did it this morning on the way in to work. Dont like it? Buy a prius.

 

Pretty normal. Checked with my tuner and he said its fine. Explained it to me and it has something with the RPM trying to catch itself so it doesn't stall out. I got tuned and then noticed it happening too like you and got freaked out. Thought it was a boost leak or something but only does it for a couple surges and then its fine.

 

Just to be sure, I would check for vacuum leaks. I don't see how idle surge can be "normal".