Need help troubleshooting an '06 sierra for 1st startup

i am having a similar problem. did you ever find a solution?

I did...turned out to be stuck injectors. They were dribbling enough gas to make it cough and sputter a little, and it would run fine on ether. I got a set of injectors from a recently run core motor from a local GM truck builder, and it lit up on the second try. He said he's seen them stick like that after as little as a year of sitting with today's crap gas. Hope that helps.

Ahhh, I see. My motor has been sitting for a year that I know of so that's where I'll start. Thanks.