But I agree with you. It's definitely NOT Seb. Just something strange post supercharger install. Saw the issue with a local nissan tuner that was around before they closed (Kaizens). Only thing left that I have not revisited is the in-tank fuel setup. I have another basket and Walbro 255 and just going to re-install and double check there. I did drill out the jet/swirl and the regulator. Was very careful in doing so.

It is definitely not the tuner. He actually gave me a couple extra tunes addressing it and gave unexpected results, more evidence that is could be something with my Z.

hmm... there was a light bulb for a second there. But, i had the hot idle issue with the HFC's before one of them blew up. I probably should have done a second leak down before going to the A-A kit. I did one before the supercharger set up somewhere between 40-50 miles just to be sure.

Check list for the weekend:

1) Pull the front bumper off again. Drive around and do a boost leak test while still hot.

2) use a vacuum smoke tester and pressurize the exhaust system, check for leaks. If anything, would be at the manifolds at this point.

3) Put the Z on the lift and pull the stock cats out and examine.

4) inspect the Fuel pump assembly. Have a new basket + pump and will re-install.

Still have yet to do this, clutch burnt out and it's been super hot here. Work got busy as well.

So... Have most of the Z apart to take the transmission out for the clutch replacement. Just waiting for a transmission lift to arrive in the mail. While I had it on the lift, I took a look at the cats. I did not remove them yet, but I noticed on the passenger side, the cell is loose. As in, I can pull it in and out with my fingers.

I'm assuming this is bad?

I'll take them off once the transmission is off and see what they look from the upstream side.

Is your Z a 2007 by chance?

It appears so

You probalbly need an 08 ecu. I had idle issues with my 07 after my turbo and my tuner said that the newer 08 ecu was able to correct throttle body and idle issues more than the 07 could.

Interesting. I think it is more of the ECU ROM type. Each ECU type has different features. My 07 Nismo ECU is EVC12

https://uprev.com/romlist.php

UPDATE:

So clutch has been switched out. Just have to put the tranny in when a set of OEM cats come in tomorrow.

I examined the cats. Besides the passenger side down stream cell that was loose, all seems in order. No clogging/melting at all.

Seb did give me a possible "Eureka" tune that addresses idle. Can't do much with it still car is back together.

Next year, I will possibly modify the exhaust. Put some resonated test pipes and put a couple of Mil-spec cells on my motordyne TDX2, possibly on the Y section of post muffler. Spent too much $$ this year.

Sounds like a vacuum leak, umm disconnect all the vacuum hoses from the intake manifold and pug every thing up, start the car and see if its still doing the same thing, if its nice and calm ~700 rpm, turn it off and connect a hose back with a new metal non OEM tie thats proven to work, start it up and check for problems, continue until you find the one that is leaking.

Boost leak checked and all is good.

Update:

Finished the clutch install... Finally. I'm only able to put in hour or 2 there and there. Married with 2 younglings takes my time away. Went with the Zspeed stage 2 quiet setup with steel flywheel. Upgraded to a Wilwood master. Can't wait for the throttle response change with the lighter flywheel.

Also got a tune from Seb for the idle. Guy has been pretty solid this summer. Have to fill up the tranny and bleed the clutch tomorrow, but I'll flash it some time this weekend.

I chased that idle thing forever. Mechanically the car was perfectly sound. I used a consult to do an idle air relearn and it was the same. Got retuned by a different tuner, instant fix.