loss of power at 3000 rpms

[juiser]

have 4.3 vortec sonoma engine ran great than had maf sensor code replaced 2x's still same results cuts out at 3000rpm's cant drive no more than 15mps/hr acting like in limp mode no codes showing but continues to be no acceleration starts perfect

[maxwedge]

Blocked cat, low fuel pressure, needs some diagnostics here.