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02 Ford Focus, auto trans. - Mysterious Issue

Heres the scoop:

while driving on the highway, after hitting the brakes hard, the engine sputters and dies for a split second, but comes back immediately after. If driving in town and we hit the brakes hard, the engine dies and the whole car shuts off.

The engine has a steady idle, but the dash guages bounce around.

My Guess: Bad alternator and/or battery. Im thinking somehow there’s a voltage surge to the ABS system under a hard brake, which drains the ignition system and interrupts the engine spark. On the highway the forward momentum of the car brings it back again, but at low speed, the momentum isnt great enough to keep turning the motor.

A friend thought it may also be the torque converter, since it locks out in overdrive - and since a hard brake would tell the trans. to downshift, somehow it interrupts the engine. shrugs

any thoughts??

What warning lights if any come on? Does the transmission/coolent light come on for a few seconds and then go off?

Are you hitting the brakes hard enough to engage the ABS? If so, why?

The battery and alternator can be tested, usually free, at just about any auto parts store. Why guess? Go have them tested.

Let us know what you find out.