anyone else get a rough idle after installing the spacer? To the point that the pedals are visibly shaking? Also the engine seems to stumble around 3k when out of the throttle.

 

you have a vacuum leak. Make sure you tightened all the bolts

 

Vacuum leak or the plenum is rubbing against the strut bar.

 

I was thinking it was the strut bar too. Clearance is kinda low, used all the washer include but I'll put some more on shortly then check for a vacuum leak. Thanks.

 

check to see if the rubber ring around the oil cap is stuck in between the spacer and plenum.

https://my350z.com/forum/engine-and-...e-problem.html

 

I did pinch it when I put it together, but I caught it before I got the strut bar back on. Good idea though.

 

Is the car actually idling rough or just vibrating? If it's a vibration most likely it's the strut bar rubbing, if it's actually running rough it's a leak somewhere. With the engine running spray some starter fluid around the bolt holes on the plenum and around the base of the plenum where the gasket mates up. If the engine revs up you've found your leak.