Q: I got a 0172 & 0420 code

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I changed my spark plugs and master air flow sensor, that didn't help. My acceleration is just a tiny bit laggy but still bothers me. The lag was worse though. Any idea? I just hit 200k miles today as well just as an FYI.

My car has 200000 miles.
My car has a manual transmission.

Hi there:

The P0172 OBD-II error code indicates that there is too much gasoline being detected in the exhaust gases exiting the combustion chamber. The ECU uses a number of instruments, such as the mass air flow sensor (MAF), oxygen sensors, and manifold absolute pressure (MAP) to monitor the air-fuel ratio of the engine. However, in many cases, it’s can be caused by a vacuum leak or a possible fault in the coolant system such as a stuck thermostat or bad coolant temperature sensor. If you’re having trouble after checking these areas, contact a professional mobile mechanic and have them complete a car is slow to accelerate inspection.

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