hey guys i'm helping a buddy out with an 00vi swap and we are having some crazy idle issues. the car with start and idle at 1700 and bouce up to 2200 and then he drove it around the shop i work at and it went all the way to 4500 and stayed. we can not figure this out. we have fixed the few spots on the intake that were leaking(we had leaks around the brass nipples we put in for the IACV and the EVAP). we just can't figure this thing out. we are thinking about putting the old stuff back on but we wanted some insight before we went through the whole process again. any help would be great. thanks

 

you have a vacuum leak, and probably a rather large one if it's idling @4500rpm

 

I hope you used new gaskets especially where the uim and lim mate. You should look at everything again and I would check the little screw on the TB as well as the idle screw on the IACV

 

are you using 4g or 5g iacv and tb?