Glad to hear you have it all figured out, enjoy the spacer!

 

yay... love md products...

 

excellent write up and nice pics. glad you found the leak. this should be a DIY, especially with the nice troubleshooting info in this thread.

 

A Mechanic at Nissan world in Springfield NJ told me that that center piece is to help guide the gasket into place, or keep it inplace. He said it makes it easier on the assembly line. Other then that, no other major purpose. Not sure if its true, but thats what I was told.

 

Great!

it will help when i install my spacer.

 

What threadlock compound did you use on the bolts? red, green, or blue?

 

Red. Its the lowest.

 

I'm bumpin this, lol. I gotta do this when I get home today, thanks vo, I was freakin out, the car stalled while I was sitting at a stop sign after installing, mine is leaking through one of the guiding pins, and must be somewhere else as well, I can run the car with a leak for a little while right? At least till I can find it?

 

vo, as an update, I luvs you right now, the oil filler thingy was caught under my plenum, thats where my leak was coming from, I just unbolted all of it, pulled it out, and the car is running like its on steroids, lol.

 

Last week the car started shutting off when I would warm restart it. For instance, if I stopped at a gas station, fueled, then started the car, the idle would drop below normal. I'd have to give it alittle gas to keep the car from boggling down and shutting off.

Last night I inspected the upper plenum. I found bolts: 7,10,11,12,13,16,17,18 were all under torqued.

I guess they had settled a bit from the last time I torqued them and began to loosen up. I re-torqued everything to 100 inch/lbs, then reset my ECU. Everything works fine now. Just thought I'd document an update for future troubleshooting...

 

Thanks for the update, Vo. Since mine has been on for a few months now maybe I'll just take a look at it this weekend and make sure they are still torqued properly.

 

No prob bro...

 

The idle problem has returned. Exact same symptoms. When I let off the accelerator, the idle drops to the point where the engine almost shuts off, then returns to normal. I suspect the same bolts quoted above are the culprits. I'm thinking about removing the bolts one by one and applying some light-strengthed loc-tite to them, then retorquing them down. The same loc-tite applied to the 6 center bolts, bolted to the top of the plenum. I forget what color the loc-tite is. I know blue is medium strength. I believe it's the one in the red tube.

What do you guys think? This will solve the issue?

 

Vo, I'm willing to guess this is your problem. That's exactly what I would do.

I checked mine the last time you posted and mine seemed to be alright... I daily drive my car with some spirited driving here and there. I actually figured that if mine needed to be tightened I would apply just a small amount of loc-tite and go from there. Let us know

 

What gets me is how they lose torque, given the little mileage I put on the car. Literally, I put about 30miles on the car per month, tops...

 

Its probably not the bolts losening.

Idle is the best indicator of good or bad sealing.

How is your idle?

 

Idle is great Tony. It only happens when I'm coming to a stop and let off of the accelerator. Or let's say I were sitting in my driveway, waited for the car to reach operating temp, then reved the engine. If I reved it, then pulled my foot off the accelerator. The car will boggle down and almost shut off, then regain smooth idle...

 

That sounds like something other than a vacuum leak.
Im thinking it could be throttle body calibration. Some of the throttle body position sensors can actually be defective. Nissan put out a TSB on it throttle position sensors.

What year is your Z?

 

2003... 39K miles

 

It was the 2003 that had the throttle body TSB.

Based on your description, it doesn't sound like a leak. I'm thinking its probably throttle body related. My second guess would be MAF sensor related.

Are you using a cold air intake? If yes, what kind?