After driving 20 miles -"bucking" and engine shuts off. Engine very hot to touch , but NO check engine sign or temp. increase. New battery, and oil change. Was told cracked radiator and, or catalytic converter, but do not trust diagnosis as-- NO fluid leaks, and coolant is full.
My car has 75000 miles.
My car has an automatic transmission.
This may be a sign of a 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 often times results in the engine starving for air or fuel. This is what causes the hesitation or loss of power you describe. This can also cause the engine to struggle to idle for the same reason.
A cracked radiator would be causing the car to overheat from the loss of coolant. The catalytic converter may also be a possibility, however this would normally cause a Check Engine Light to come on and the car would have more of a sluggish feeling to it rather than a bucking response as you describe.
To avoid any unnecessary repairs, I would suggest having a professional from YourMechanic come to your home to diagnose your stalling issue and replace this sensor if necessary.
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