brake pedal pulsating

You say it pulsates when you push in the brake to start the car???? Well from that info alone, we can count out the rotors as the major prob. Warped rotors are the most common cause of a pulsating pedal, but they can´t make the pedal pulsate if the car isn´t rolling. The initial pulsating is more than likely from the ABS unit. Once you turn the key the servos in the ABS unit enrgize and go though a self test program. While they are going through the self test they tend to hold and realease presure which would cause the pedal to pulsate a bit. If your ABS light goes off within 5-10 secs after you start, you should be ok. Next time you start your car, check to see if the ABS light starts blinking randomly. If it does, it may be outputting an error code and you should take it to the dealer or qualified Ford mechcnic to get it checked out. The ABS could be causing the pulsing while you are driving too. Do you have the stock size tires on your car??? If you put lower profile tires, smaller rims on your car, or even low tire pressure the speed sensor will think you are slowing down faster than you really are, and could kick on the ABS. Another thing is the system may need to be bled. You will want to check the service manual before doing it your self, because some ABS system can hold up to 2000psi in reserve and once you open the bleed screw, it could do some real damage to you or your car. Let me know anyother info you can about this prob and I´ll try to help out asa best as I can.

The car was just inspected and the rotors and drums are fine. The car doesn´t have ABS but we did pull the fuse to make certain that wasn´t a problem. I have also just replaced a check valve to make sure that it was holding vaccuum and it still pulsates. It pulsates while braking now. I wonder if it might not be the master cylinder is going bad?

I replaced my brake booster even though it tested fine and it fixed my pulsating brake pedal. Finally my car is back to normal...

Thanks for all your suggestions.