I am debating with my buddy about, Converters and oxygen sensors, he has a 02 prix non supercharged 3800. He bought it from a younger kid and the car had a bad maf sensor, so no telling how long the previous owner drove it like that. So a bad cat is totally possible.
He changed the maf ,and the gas mileage went from 11.6 to about 11.8 miles a gallon and he has a PO420 code. I know that code can mean many different things. But The debate from my stand point on these cars the only time a cat can cause bad fuel mileage if its clogged. I don't think the rear o2 sensor does anything but read what the cats doing, It doesn't change fuel trims etc.. But I could be wrong of course.
We did the the restriction/back pressure tests (the easier ones) with the gauge hooked to the intake manifold. Not sure if those are good enough and they all can back with normal readings.
I suggested he do a tune up first, car has 99,000 on it.
He changed the maf ,and the gas mileage went from 11.6 to about 11.8 miles a gallon and he has a PO420 code. I know that code can mean many different things. But The debate from my stand point on these cars the only time a cat can cause bad fuel mileage if its clogged. I don't think the rear o2 sensor does anything but read what the cats doing, It doesn't change fuel trims etc.. But I could be wrong of course.
We did the the restriction/back pressure tests (the easier ones) with the gauge hooked to the intake manifold. Not sure if those are good enough and they all can back with normal readings.
I suggested he do a tune up first, car has 99,000 on it.
