my truck started breaking down my engine light flashes on and off the truck will start and run but has no power on exceleration or going up hills i have replaced the spark plugs wires and map fuel sed

if the ses light is flashing its running excessive rich/lean enough to damage catalytic converters , need to scan engine data to find why

What's the mileage? Don't matter its 2001 most likely the upstream oxygen sensors replace both up and down sensors on both cat converters. I need to do the same on my truck too 3.9 v6 dakota