Hi John...Long time, no talk.
I have a favor to ask of you. I am helping a friend with an LQ4 conversion and am experiencing conditions very much like you had with your conversion. This is a 2003 that was mated to a 4L80E. My buddy is using a turbo 350, so it essentially behaves like a manual tranny. Like you, I have the JET DTS. After turning off the VATS and other stuff, I flashed the VCM with the switch telling it that it had a manual transmission. It starts, but appears to be in "limp" mode. It idles just fine, but any throttle results in crap.
What did you ending up doing to get your engine to run above idle? Do you have a JET DST calibration file (*.jcl) that works for your engine that you might share with me.
Any help will be greatly appreciated, John
Jack