Q: Car jerking

The hole drilled into your MAF sensor has altered the metered reading of air being injected into your car. 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. The excess air that is now being supplied to the motor is causing 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. Often times when making modifications to the intake, an aftermarket MAF sensor is required in order to compensate for the change in air as the factory sensor will not always re-calibrate. I would suggest having a professional from Your Mechanic come to your home to diagnose and inspect your vehicle.