Goes lean once it reaches operating temp, car dies.

[Tengis]

Ive got a buddy with a car that has had all kinds of misc issues. RB20det swapped schassis car with 11u0f for RB25 so that we can use the TPS idle trigger instead of his rb20det TPS. He is running the popular chinese fabricated front facing manifold that companies like Zerofab sell.

We have actually just realized that a few of the issues we thought his car was having turned out to be just one: When the car reaches operating temperature (65+) it will randomly decide to creep lean until the car dies and will not start back up until the temperature reaches below 60-65ish again. As far as I can tell there are no sensors that we can read that are failing, but the O2s do start to get funky but I think it may be primarily because of the lean condition.

Fuel pressure is good, injectors shouldnt be an issue (we have tried a couple sets to try to solve another issue), have swapped around different MAF sensors (stock RB25, a couple different Z32), and I had him install an idle air control valve and plumb it in properly. He is running a blow through MAF setup about 10 inches from the throttle body instead of the stock draw through. Stock RB20det ignition setup, stock CAS. Hes never had this car running since doing all of this stuff and installing Nistune... he has gone far enough into thinking he was having physical issues that he bought a brand new wiring harness from wiring specialties and redid his wiring for a few other things like the fuel pump.

Anyone have any idea what could be causing a lean condition? Something in the ECU I could be missing?

[Matt]

Can you take a log of the issue, showing the drop off in temperature and also a copy of his current maps

It's the only way to see what is going on. Looking at the issue description alone, I have no idea what is going on

[RomChip200]

Log rpm, temp, inj. ms, O2 long/short trims, TP, timing.