I have a jdm h22 into my CL. Heres the deal, my car idles very smoothly (can barely tell it's on), but precisely between 1500 and 2000 rpm it surges up and down. I'll sit in the car will it's in nuetral and rev it slowly and when it gets to 1500 it'll start the jumping up until 2000 rpm, after that it's smooth again, do you have any idea as to what the hell is causing this? Thanks, Leon!

 

idle control valve. check the two hoeses that come out of it and replace them with new ones. mine usually does it when i have my distributor advanced all the way

 

advance could be the problem, I remember when my swap was done my mechanic was twisting my dizzy back and forth. turning it to the front of the car is advance right and turning it to the firewall is retard? correct me if i'm wrong!