Q: Car jerks and slows down

asked by on November 06, 2016

When I'm on the highway going 70mph, the car would jerk when I press on the gas and the speed would drop down to about 50 or 40. When I press on the gas it either does nothing or the car jerks even more. If I just drive at that speed for a while it goes back up to 70. I usually drive to places closer than 30mins away and I don't have this problem. However, I need to drive 4 hrs to visit my parents a few times a year and that's when this happens. I have to drive home to vote on Tuesday and I'm wondering if the car can make it.

My car has 200000 miles.
My car's transmission is unknown to me.

Hey there. This may be a sign of a dirty or failing mass air flow sensor. The mass air flow sensor is a unit in the intake system that monitors air intake as it is mixed with fuel prior to being injected into the motor. When this fails, this 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 is what causes the hesitation or loss of power you describe. This may also cause a jerking type reaction by the car when pressing on the gas pedal as you describe. I would suggest having a professional from YourMechanic come to your home to diagnose the jerking issue and move forward with repairs.

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