My 1995 Lexus GS300 has 3 OBD codes:
21 - Main oxygen sensor fault (left bank [radiator side] oxygen sensor)
27 - Sub-oxygen sensor circuit fault
28 - Main oxygen sensor fault (right bank [firewall side] oxygen sensor [ 02 sensor ])
It also has an exhaust leak right after the front catalytic converter (see the image).
I want to clean the MAF sensor and throttle body since I am driving a lot during this summer and am hoping to improve my gas consumption.
Is there any point in cleaning the MAF sensor if all three oxygen sensors are bad? I think they all are connected: MAF regulates the air flow, oxygen sensors regulate how much fuel to inject in the next engine cycle.
I think it is worth cleaning if it is easy to get to, but not if it is hard to take apart. The reason I say this is because it doesn’t seem like the MAF is the problem. If it ain’t broke don’t fix it. But if it’s easy to clean and it doesn’t harm anything, why not do it?
If I understand MAF sensors and O2 sensors correctly, the MAF will send it’s data to the ECU to make adjustments to the fuel injection. And the O2 sensor can also contribute its data to the ECU to make more changes.
Ideally you would have all working at the same time. But I’ll take a clean MAF with good “data” over a dirty one.
Cleaning the MAF sensor is easy, whereas getting to the throttle body is very hard on this Lexus. In another thread, I was recommended to clean them both because (once in 2 years) the car stalled when decelerating while going uphill.