Hey all, I have a 2004 lj unlimited. I am having horrible fuel mileage... I changed the water temp sensor did not change a thing so the next is oxygen sensor or vaccum leak. For the sensor which one would be the problem.
Which oxygen sensors control fuel adjustment?
- Thread starter Yahuah
- Start date
The upstream O2 sensors above the two small pre-catalytic converters. If you replace them make sure to avoid Bosch and use only either NTK or NGK O2 sensors.
Bofa-Deez
TJ Enthusiast
OP
I would need to replace both of them? Could the sensors not cause the engine light to go on or throw a code?
Bad O2 sensors rarely throw a code, the computer isn't usually smart enough to know when one or both are lying. And without a specific code pointing at a specific O2 sensor I'd replace them both if you suspect they're the cause of the poor mpg. And one or both are certainly more than capable of doing just that.
OP
