Originally Posted by
L1FTD
Perfect! Great info!
So you had the problem stock exhaust, but injectors added.
Myself and others had the problem with stock injectors, but exhaust/intake mods.
Seems like it is pointing to a factory intention, worked in there by GM for emissions most likely.
Whatever is going on, big injectors and possibly no cats just amplifies whatever GM intended to do with the leaning out.
Very consistent, could be an oxygen storage thing like GHuggins mentions. Need to find the parameters. If it is in the FSCM, not much chance.
So many variables have been discussed in sgod1100 thread. Everyone noticed the issue at a different point in their mods, no one could confirm if the car did it completely stock.