LT-1 issue

[John Nechiporchik]

Fired up LT-1 after rebuild and all appeared to be well. At initial start up, only ran the engine to around 2500RPM.
Loaded up and went to track.
At track, warmed up and drove to tech and back to trailer. went to 3000and all was well
After adding fuel to cell and a quart of trans fluid, headed to lanes. Car would not accelerate driving to lanes, headed back to trailer.
As it sits now, car will start, idle, and immediately stumble as the throttle is opened...like it is not getting fuel.
Gas was a new sealed container of renegade 110+
Fuel map same as last year
Rebuild included new rings, bearings, cam, valve springs and a different set of heads.
Before initial start, I flushed the fuel system and replaced the fuel filter.
Looking for possible causes.
Bad fuel?
Throttle position sensor?
Any ideas??
Thanks for any help.

John