LQ4 Swap Not Running Right

[72longhornTX]

Alright everyone, I need help. I am at a loss as what to do next.

I have been searching here, google, ShopKeyPro, and anything else I can.

Here is what I have.
71 C20
2001 Silverado LQ4 6.0/4L80E.
Computer done by Brendan and LT1Swap
Wiring harness cleaned up per his website.

My problem I am having, short of the couple oil leaks which I can deal with easy.

The truck starts fine when cold and idles great for about 30 seconds to a minute. Right around 600 RPM. I am using a Snap-on Modis Ultra to view live data. However, after that time the idle starts going low and the engine starts chugging and shaking. If I let it keep doing that, it'll die. If I press the gas it takes a minute and then catches up but once I let off, it goes to the same thing and dies.

If I try to drive the truck, once I let off the gas it dies. Common problem here is, it dies.

I have pulled the throttle body, cleaned it using a parts washer, pulled the IAC and cleaned it. Put new AC Delco plugs and wire on the truck and I am not getting a single misfire.

Just can't seem to figure it out.

As for codes, the only ones I get are when I unplug a sensor to see if something changes. No MAF code, no IAC code, infant the readings on the IAC are on spot with what it is requesting and what it is giving. I have checked the fuel pressure, 55psi at idle and 58psi when I unplug the vacuum regulator on the rail.

This is a drive by cable engine as well.

Any advice is greatly appreciated and if anyone who knows a lot about this on the west side of Houston, feel free to invite yourself over, I can provide beer and BBQ. I just need to figure this out by Sunday night, This is suppose to become my daily driver.