Elantra MD (2010-15) :: Loss Of Acceleration Suddenly While Still Pressing On Gas Pedal

My Hyundai Avante (2011 model 1.6) suddenly loses acceleration while my foot is still pressing on the gas pedal. Every time that happens I have to raise my foot from the gas pedal and press it again to make the car accelerate. This thing happens randomly, but mostly at speed lower than 80 Km/h

I tested the car on an empty road once; I didn't raise my foot from the gas pedal this time when the car lost acceleration. The car speed dropped to zero and the RPM gauge returned to idle (i.e. around 1000 RPM).

The check engine never light up during or even after this thing occurs. Here is the list of things the mechanic tried on my car:

1-Cleaned the body throttle
2- Tested the car with another used body throttle
2- Tested the car with another used gas pedal
3-Check the fuel pressure and injection
4- Checked the sparks
5- Tested the car onboard computer.

None of the above worked!!! Here is the strange thing my mechanic discovered, if he unplugs the cable of the Anti-lock braking system in the car. The problem never occurs.

I have been driving the car for two weeks, with the ABS system unplugged. The loss of acceleration problem never happens. I am not sure what the ABS has got to do with the car acceleration.