My truck seems to be losing power. Takes forever to get up to speed on highway. on 1996 Chevrolet S10

REALLY bogs down on hills
Fuel pump replaced on 5/22 along with fuel filter and several inches of fuel line on either side.
Diagnostic machine at O'Reilly's said that the system was "too rich"

2 answers 2 comments
that means its running rich ck fuel trim and fuel delivery issues you may have stuck open injector
How would I know which one to replace? One at a time trial and error?
get a proper diag
Don't guess, have it tested by a qualified tech. Unless you have money to waste.