COORD BTWN TRACON AND TWR PLUS CHANGING WINDS CAUSED TWR TO ISSUE GAR TO RPTR FLC WHILE STILL AT 2000 FT ON APCH. POSTFLT REVIEW WITH TWR INDICATES THERE WAS A WIND SHIFT THAT CAUSED LOSS OF SEPARATION ON APCH.

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AT 10 DME EWR TWR ASKED FOR 160 KTS TO THE MARKER. WE WERE MAINTAINING 170 KTS AS REQUIRED BY NY TRACON AND SLOWED TO 160 KTS. IMMEDIATELY; TWR CALLED BACK TO TELL US WE HAD A 50 KT OVERTAKE ON A B757 IN FRONT OF US AND THAT WE HAD 4 1/2 MI SEPARATION. WE CONTINUED TO CONFIGURE THE ACFT AND BEGAN TO SLOW TO APCH SPD. AT 8.5 DME TWR AGAIN CALLED TO SAY THAT NOW OUR SPDS WERE COMPATIBLE AND TO AGAIN MAINTAIN 160 KTS TO THE MARKER. THE TWR CTLR ALSO SAID THERE MUST HAVE BEEN 'A BURP ON HIS MACHINE' THAT MADE HIM BELIEVE WE HAD ORIGINALLY HAD A 50 KT OVERTAKE. WE AGAIN INCREASED OUR AIRSPD; NOW FULLY CONFIGURED TO 160 KTS. AT 5 DME; WITHOUT ANY PRELIMINARY WARNING; THE TWR CTLR TOLD US TO EXECUTE A MISSED APCH. HE GAVE NO REASON. THE MISSED APCH WAS UNEVENTFUL AND WE LANDED APPROX 30 MINS LATER. I CALLED THE TWR ON THE GND TO FIND OUT WHAT HAPPENED. THEY TOLD ME THAT A 'WALL OF WIND' WAS SLOWING ALL ACFT SIGNIFICANTLY AT 500 FT AGL. IN THE ACFT OUR INDICATIONS SHOWED A 30 KT HEADWIND AT 2000 FT FROM 25 DME TO 10 DME. IT DECREASED TO 15 KTS AND STABILIZED AS WE PROCEEDED DOWN THE GS. THERE WERE NO PIREPS FOR WINDSHEAR.