Toyota tercel 1999, automatic 4 doors ,Car consumes too much fuel, had a code p0125 the culprit was O2 sensor not the thermostat nor the coolant sensor, thought it will fix problem but still chugging fuel, changed spark plugs, still the same, no engine code came after changing sensor, car runs fine no hesitation, idles fine, its doing about 16L per 100KM!!! It's bugling my mind , it can't be tires pressure because I check it all the time, no fuel leaks, no air flow leak, the consumption amount is just ridiculous for the average mpg of this kind of car!! What's the culprit for the good sake of small fuel economic cars!!
My car has 80000 miles.
My car has an automatic transmission.
A P0125 code says that the engine is not reaching sufficient temperature to go into "closed loop" operation. Closed loop operation is essential for fuel economy and low emissions. Basically it’s saying that your engine is not warming up. Replacing the thermostat was a good move, but you should try to measure the coolant temperature to see if it agrees with what you would read on the scanner. It could be that the coolant temp sensor is in error of the sensor ground is not solid. If you want help with this, contact Your Mechanic. They can send a technician to your home or office to check out your gas mileage issue and tell you what can be done about it.