Ok I have a 90 crx si coverted to obd1 with a d16z6 swap. I've had the swap in there for some time now with no problems. I am getting it ready to drag race again this year, so I pulled the z6 manifold off and swapped it out with a y8. I went to start my car just to test it out and the idle is at 3000rpm if i unplug the iacv it goes down to 1500rpmish but it bounces. So then I thought the iacv was dirty so I took the know good one off the old z6 manifold and it does the same thing. I've gone over the vacuum lines and went as far as capping them off one by one and the only thing that made a difference was unpluging the iacv. The only other thing I can think of is I took the radiator out to put on my new traction bars and I dont have one installed (a radiator) right now nor is there any coolant in the engine. Would this have anything to do with it? I wasnt starting the car to drive it just check and make sure everything was OK and it's obviusly not! Any advice?

 

Fixed! It took 3 days of searching to find out that there is 4 little holes on the manifold (one above each injector) that leak air. Its only on the 99-00 y8 manifold. I jb welded them shut and it now works great!