finally something showed for codes

she took her 96 s10 4.3 vortec for emmission test here were the results from the computer

trouble codes
po171 system to lean
po174 system to lean
po719 torque converter/brake switch b circut low

on board computer indicater light command on

can anyone help translate- any suggestions on what needs to be checked replaced or repaired as always your help and assistance is very much appreciated Dave

How many miles on the vehicle?

How many miles since the last tune up,
(plugs, wires, distributor cap, rotor, plug wires & fuel filter)?

Have the oxygen sensors ever been replaced?

Does the vehicle have an aftermarket air intake system?

Have you checked/cleaned the Mass Air Flow sensor?

Have you checked fuel pressure & leakdown?