02 sensor

so my truck threw a code. Bank 1 sensor 2 is out. But the thing is I’ve lost maybe 1-4 mpg and no performance and light will go away and come on as it pleases. Anyone else have this problem. It tends to come on when I drive it hard

 

Since you don`t mention just what code has been tripped .

It could be as simple as a exhaust leak when things get really hot.

Physical damage to wires allowing the circuit to open and close at random

 

Replace both sensors. Go to Denso Site and put in the specs of your vehicle

 

There are no codes that say a part is out. For any code you have to go to the repair manual and follow the test procedure to determine if a part is actually bad. It could be a broken wire or something else.

The back O2 sensor just monitors if the catalytic converter is working correctly. It could be a bad cat, exhaust leak, broken wire or bad O2 sensor, etc. The back O2 sensor isn't used by the ECU to control the engine or fuel. It's only there to monitor the cat, so it's not surprising that your performance hasn't decreased.

 

Simple things first. #1 FUEL,,,, Gasoline is not what it used to be. +Ethanol ranges may exceed 17 at the pump. Try a tank of Ethanol free if aval. in your area. Ethanol absorbs water which when burned changes exhaust gas chemestry decreasing cat performance and lifespan of cats and muffler. Look for rust inside exhaust pipe end and water puddle on the ground while idling hot engine. Interesting to watch at a stop light how much some cars produce and how little others dont.

 

FYI If you think the fuel is a closed system check your oe gas cap. There is a vacuum relief valve there which allows moisture filled air in as the fuel cools. This time of year with high temp days and much cooler nights are perfect conditions for water to enter your fuel via ETHANOL.