Not probably gonna get much of a reply on the EFI front here anymore. This forum died when custom tuning did. Your best bet is to just call a reputable shop and hope for the best.
2018 GMC l5p ccsb stone blue metallic. Mcgaughy's 2" drop shackles. Truxedo tonneau cover. 20% tint. B&W turnover ball hitch. N Fab running boards, Duraflaps, Rhino lined bed
Traded:05 lly ccsb 205k miles, built trans and supporting mods
Traded:09 LMM CCLB Bone stock, fully loaded. 86xxx miles.