Meotta

I have recently installed the skunk2 intake manifold and throttle body on my 97 turbo Miata. I read all the posts about potential issues and have already installed a beefier throttle cable bracket and drilled the new hole for the throttle body spring and have checked that it is closed.

I had the idle tuned pretty well and then did my first track day since install and after about 25 laps I came into pit road and the car was idling at 3500 rpm for some reason. I though it must be a vacuum line or something; but all of the lines are good and the throttle blade is shut at idle. I can't seem to find the leak with a visual inspection. Luckily, I only live 10 minutes from the track and was able to drive it home.

I am also using the intake manifold spacer and am now wondering if the gaskets included with the skunk2 manifold and spacer are not keeping it sealed up.

For those of you that also have the skunk2 manifold have you had any issues with vacuum leaks? I am considering taking it apart and using black rtv instead of those gaskets; but not 100% sure that it is even the problem.

Gee Emm

I have installed three of these TBs on my cars over the years, never had this problem. Can't comment on the manifold though. If you have a spare idle control I'd swap it in just to rule out something there, because it is easy.

Otherwise, if you have checked everything else and found nothing, then what is left is probably the problem ...

Z_WAAAAAZ

Best way to figure out a vacuum leak location is to run the engine at idle and spray brake cleaner around the entirety of the intake manifold/vacuum lines. I recently had a vacuum leak from my Skunk2 TB when one of the IAC valve adapter bolts backed out (should've loctite'd those, D'OH!). The car was idling at 2k rpm and I could hear the leak but couldn't pinpoint it due to the location it was in (under the manifold/behind the throttle body). After spraying brake clean around for a couple minutes, the location was pretty obvious due to the idle droop when the cleaner found its way into the leak.

Not saying that's necessarily your issue, but I'd do the brake clean test before any further diag.

Lokiel

Z_WAAAAAZ's tip is great (pos-cat added since I'd forgotten that one), it's SO simple (the important bit though is to do it ONE point at a time):

Gee Emm

Never heard of that one, that's a great tip now added to the memory banks.

Meotta

Just an update, the problem was the IACV. It crapped out and is stuck wide open. Unplugging it makes no difference, it is stuck wide open and sucking tons of air. If i cover the intake pipe for the IACV the car shuts off.

I have it sorta fixed, I capped the intake pipe for the IACV and unplugged it and then cracked open the idle air screw on the throttle body. Its now idling fine at 950rpm when warm. Cold starts might be an issue though.

I might end up just removing the IACV and using a block off plate on the bottom of the throttle body. I have no AC or PS and live in southern GA where it doesnt get too cold.

Z_WAAAAAZ

Appreciate the follow-up!