I have a 2014 hyundai genesis coupe 2.0t my car is stock except for a short cold air intake. When I turn the car on I feel the car with boost and also when I drive it in low rpms, but when I step on it hard I got no boost and the car goes into a "limp mode", no boost at all after that, I got no CEL codes or anything, just no boost. I have to disconnect battery to reset everything but when I drive it again is the same story.
My car has 37000 miles.
My car has a manual transmission.
Depending on the cold air intake, you may be affecting the readings from the mass air flow sensor, which may be causing the motor to stumble when pushing for more boost as you describe. The mass air flow sensor monitors air intake as it is mixed with fuel prior to being injected into the motor. This sensor relays vital information to the ECM which uses this to make adjustments to fuel supply to the motor. A dirty or faulty sensor can cause an imbalanced air/fuel load to be supplied to the motor which results in an over fueling or under fueling situation depending on the conditions. This type of inconsistent fuel supply to the motor may cause a hesitation, loss of power, a jerking reaction, potentially a bit of black exhaust smoke and typically a strong smell of fuel when this sensor is malfunctioning. I would suggest having a professional from Your Mechanic come to your home to diagnose and inspect your vehicle.
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