Sputtering issues after sitting

[Kyoshosp2]

Car idles fine . But after 1500 it's starts to sputter .. If I give it gas it sputters and backfires a little too . But clears up after 3500-4000rpm .. Now for some history on the car .
I bought it and it was in a garage for a few years and parked with a full tank ..i bought it a month ago .. Tank was full of rust and pump assembly rusted up and pump seized .. Put a good battery in and started car in either and it ran and revved fine on that .. Now I acid washed tank and a take out running pump assembly .. Is in . And new fuel filter and fuel line flushed . Now it reves and sputters .. Also the CPU is new . 600.00..

So wondering if it's in the rails or injectors .. Since it ran on either fine .. I have the manuals .. But where to start looking ?


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[Kyoshosp2]

[Kyoshosp2]

Any ideas