2003 Chevrolet Malibu Q&A
2003 Chevrolet Malibu Question: Bad gas mileage
Have you had the catalytic converter checked as if its clogged engine performance and mileage will be affected. - hemicuda
A professional grade scan tool allows you to look at live sensor data. If the coolant temperature switch reads low the computer will enrich the mixture, if Oxygen sensor readings are low the computer will enrich the mixture. Another key sensor that affects is air flow values. Also important to look at fuel trim values long and short term to see what is going on. - patrick mannion
You need to have someone scan it with full computer scanner, not just a code reader. Hopefully the person that is scanning it will know what to look for. Short term and long term are really not abnormal. Just because the O2 sensor is new doesn't mean it's good. What does the upstream or sensor look like. What do you consider bad mileage. I have a 3.1 in my car and the best I have seen is intown 18 highway 21. - backyard tech
diagnostic code came up as bad oxygen sensor or catalytic converter, it happened today and I smelled strong odor of gas and the gas mileage just started to be very poor but the car runs well and i...
I have the V-6 engine and the gas mileage I think is not good ! Why is this and what could I do to fix it?The manifold gasket is leaking now ,what that cause poor mileage?