2010 silverado 5.3, LSA blower, 212/218 vvt cam,3 bar map sensor. When giving gas to start rolling from a complete stop timing gets pulled/afr goes lean but nothing in the scanner is commanding the pull as far as I can tell. Truck will almost die then take off once timing comes back Log files shows when I give it a bit of a gas the idle spark goes from 14* to 0, sometimes slightly negative. Once it gets rolling (over 1100 rpm/4-5mph) truck runs fine. Dont know where to start.
Thanks for any help.