I've got an lt10s. While the car's idling, if I plug the vacuum line from the microtech into a nipple on the intake manifold, it dies.
It won't start if it is plugged in.

I tried fooling around with the load and water maps a bit with no success. Any ideas as to how to fix?

 

Um, so you are saying that the vacuum source to the Microtech is disconnected?

That's the primary load sensor. Manifold pressure, combined with RPM, is used to determine engine load.

If you didn't have that sensor connected and started tuning the engine, then connecting that sensor will instantly invalidate that tune as the ECU will now be using the entire fuel map instead of the 0" row only.

 

Thanks for the info..
I've since reconnected the vacuum source and loaded with the base maps provided by silverrotor with no success. It'll stumble, fire, but won't idle. If I get it to fire, then pump the accelerator, it'll rev, but if I stop pumping to allow it to idle it dies immediately.

 

Fuel pressure?

What you describe is a lean condition.

What are your primary injector PWs while cranking and while the engine stumbles?