I installed the AAM angled plenum spacer on my 2003.5 6mt sedan a couple of days ago and all is good except the car idles very low and very rough. It almost sounds like it is going to die out. I disconnected battery for 12 hours but this did not help. Any suggestions? Do you think the ecu reset will work?

 

You've got a very small vacuum leak somewhere. Vacuum leaks cause poor/low idling because unmetered air is getting into the engine. I suggest checking all the bolts and the intake tract for proper torque and assembly. There is a very specific sequence dictacted by Infiniti on how you're suppose to torque down the upper plenum bolts. Not following this can lead to leaks.

 

What DaveB said. Did you plug up all the nipply things? Some installs showed certain vaccum lines that have been removed and need connected back up. On may have accidentally popped off. Re-check how it was bolted up as well...Good luck and let us know what it was.

 

Also;
Check the bracket for the intake tube (behind the oil fill)
It can sneek under the edge of the spacer & cause a leak.

 

Thanks for the info. Does anyone know where to look for the correct sequence to tighten these bolts and what the torque speck is?

 

Ok. So i checked if any brackets were in the way. None are. I check both gaskets and they both look good. I tightened bolts in the correct order and to proper torque. I still get the rough idle. It starts to idle aroun 600-700rpm then drops to 500-550 for a few seconds and is rough, then goes back up and is smoother, then goes back down, etc. Only idling is rough, acceleration is smooth. I do hear a faint whistling sound at idle. Could the spacer be warped? I need help.

 

Have you contacted AAM?

 

khan29
That's so typical of an air leak bro.......Same thing happened to me the first install of my plenum (Crawford). The rubber gasket around the oil fill got pintched under the plenum. Easy to miss.

Another issue was that one of my plenums did not sit flat.....it was slightly warped from poor machining, thereby not allowing a good mating surface. hence a leak.
Since yours is just a spacer, I doubt that is an issue. In any case, installing 2 gaskets (back to back) was a good quick fix. You did put a gasket on both sides of the spacer????????? All mating surfaces need a gasket right...

As far as I know the torque specs for the plenum bolts are about 10lbs. Very easy to crack the castings if you over tighten. Use the correct cross bolt tightening sequence and you should be fine.
The 1/water and 2/air recirc. at the rear could be another difficult spot to get tight and right, as is the throttle body's 4 Allen 'bolts and gaskets (same area).. If memory serves, the tab on the T/B's gasket should be pointed up.
On the passenger side, is another bigger air recirc. hose that may not be on correctly. near that on the plenum itself is another aux. nipple that should have a small black nipple cover on it to seal.(same as the OEM plenum).

Now you get into the rest of the external inlet piping. (Z-tube, MAF piping & electical connector, and clamps. All must be on tight without leaks, and could be easily misinstalled due to cramped, hard to see areas. If you've got a Z-tube installed the recirc. hose that is usually on top of the Sedan's OEM inlet could be on the bottom and hidden.. make sure that's on and tight.

That's all I can think of now.

Good luck with the fix. Pretty sure you missed a hose tho.

C.

 

Almost forgot, khan29, Welcome to G35Driver, and congrats on the G.

Please post up when you find the air leak.

C.