Oxygen senser check engine light keeps coming on and going off. took it to auto zone they ran diagnostic and said it was running to rich. that could be the oxygen senser correct. and how difficult would that be tyo replace myself, never have done that before?

try replacing the o2 (oxygen) sensors on the exhaust pipes. there should be at least 2 of them.
if that does not work then your next option would be to have the catalytic converter inspected to see if it is plugged. (poor acceleration)

It means your car is not reading exaust flow properly. The banks is a term for the exaust coming from either side of the engine. More than likely you need new oxygen sensors.

Sounds like the timing is off a bit!

Fault Code 51 - Oxygen sensor output indicates lean too long

Power loss light: Off
Limp-in mode: Engine allowed to run rich, but prevented from running lean

Possible Causes
Bad oxygen sensor - Replace the sensor which is located on the turbo housing near the down pipe (for turbo) or on the down pipe near the exhaust manifold.

Bad connection or wiring - Check the wiring and connections between the sensor and the logic module (or SMEC). Clean and regrease any corroded connectors with dielectric grease and repair any shorts. Look for melted wire insulation near the exhaust manifold. A shorted connection to ground or any positive source will cause this fault code.

Low fuel rail pressure - See the Diagnosing Your Fuel System page.

Diagnostic Method - Trigger Parameters
- In closed-loop
- Sensor output indicates lean for more than 715 seconds (11 minutes, 55 seconds)

Results If Component Fails
A fault code 51 is stored, the circuit stays in closed-loop, and the logic module will still monitor the oxygen sensor signal. If the condition persists for four times what it took to set the code, the logic module will allow the engine to run rich, but prevent it from running lean.

Hope helps.

The Check Engine light comes on when the ECU detects a problem with the emissions system. Rarely does it come on and then go off again. Make sure your gas cap is tight. Turn it until you hear it click 3 times. If that is not the problem then you need to have the ECU scanned with an OBD2 scan tool if the light comes on and stays on. If it just comes on intermittently then do nothing until it stays on all the time which it eventually will.

p0172 is--system to rich ( bank 1). an oxygen sensor on bank 1, detected a rich condition ( to little oxygen in exhaust ) v6-v8 - v10 engines, bank 1 is the side of the engine that has # 1 cylinder. causes could be a vacuum leak in a hose, a dirty or bad maf sensor, or fuel pressure or delivery problems.

If there is an AUTO ZONE around your area, have them scan the truck for any DTC codes which would help us understand why there is a check engine light at high way speed. It could be a misfire to transmission problem, to having the engine run lean or rich to a faulty fuel pressure regulator. Good luck and keep me posted, be glad to help get your truck running 100% again soon. 

Replace the oxygen sensor

Quite often that is to do with your Gear Position Neutral Safety switch.

Hey check this out , may be your Ctalytic converter or Oxygen senser is bad