1992Vortec

Hey guys so I converted my TPI to the HSR and after the install on decel it goes lean and backfires though the intake till i give it some gas. never had the problem before and Also my wideband reads a lot different than before this install. On cold start up at idle it runs lean like 15-17 then after it warns up it runs good 14.7. now at a curse its leans back out to around 16 but just a touch more gas it runs rich then tries to settle at 14.7. WOT it runs 11.5 no matter what i do to the fuel pressure this is what it runs? ive tried 40psi vacuum disconnected all the way to 60psi. Any ides would be great I im going with the EBL and want to make sure i don't have any mechanical issues before trying to tune out a issue and losing. thanks!