1999 Pontiac Grand Prix Car Starts Runs Great Noise Etc However Come Stop Makes

1999 PONTIAC GRAND PRIX
160,000 MILES
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CAR STARTS AND RUNS GREAT NO NOISE ETC,HOWEVER WHEN I COME TO STOP IT MAKES A HUMMING SOUND.ALSO IF I PRESS THE BRAKE ON AND OFF AT STOP THE CAR HUMMING GETS LOUDER AND THE CAR SURGES.PS WHEN DRIVEING DOWN THE ROAD NO ISSUES ONLY WHEN I COME TO A RED LIGHT OR STOP SIGN. I CAN CRANK IT UP IN THE DRIVEWAY LET IT RUN NO MISSING OR HUMMING. THS GOT ME PUZZLE
Mar 21, 2013 at 2:49 PM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 POSTS
It sounds like you have a vacuum leak either going to the brake booster or the booster itself. Check that.
Mar 21, 2013 at 6:04 PM
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