2001 nissan frontier 3.3 auto runs horrible

2001 nissan frontier 3.3 auto, bought cash from
used car dealership 16 months ago. Check engine
light and ever so slight miss occassionally, finally
coded while happening knock sensor. One year
later pinhole leak in heater hose squirt like water
gun across top of motor around 10 o'clock position
sitting in drivers seat. Go to parts store get nipple
to bypass heater core. Pop cap while running to
add water, of course back blow all over front of
motor and distributor. Multiple misfire. Auto parts
store codes knock sensor, O2 sensor, multiple
misfire. Change #2 downstream O2 sensor (per
obdII scan) runs perfect 30 seconds then back to
barely running. Bouncing like it's beating itself to
death. Wait a week for everything to dry, no
change. Take it to nissan dealer in Paris tx
(supposedly the closest real time diagnostic
console) 10 days later they call and say dist cap,
rotor button, plugs and wires. All new, no change.
Missing so bad truck visibly bounces, horrible
mileage, can barely reach overdrive and cannot
keep it. Even in 2'ND and 3'Rd loses speed going
uphill. Still only codes knock sensor, O2 sensor (the
same one) and multiple misfire.