2007 Nissan Quest engine running rich. No error.
I own a 2007 Nissan quest. Bought a year and a half ago. About 3 months ago we had the catalytic converter replaced due to an error message that was showing upand the mechanic said would fix it. The error message did disappear, but our gas mileage tanked and we currently get 13 to 18mpg. There are no errors in the computer, but when I use the torque app it notes the engine is running rich which is exactly what feels wrong. I want to replace the O2 sensors but they are fairly expensive especially if the repair is not needed. Should I suck it up and just bu do the sensors? Should I just suck it up and keep driving? Our should I bring it into Nissan and have them figure it out? Sell the car?