AN ACR B767 FLC WAS VECTORED OFF OF THE STAR RTE THEN GIVEN AN ASSIGNED SPD THEN GIVEN A CLRNC DIRECT TO A NAVAID THAT WAS ON THE STAR RTE. THE FLC INTERCEPTED THE STAR RTE AND FOLLOWED THE CTLR'S INSTRUCTIONS TO DSND; BUT WERE UNSURE IF THEY SHOULD MEET ALL OF THE STAR RESTRS. THE CTLR EXPECTED THEM TO DO SO; APPARENTLY.

Narrative

WE WERE CLRED DIRECT TO BORGER; BOWIE THREE ARR DFW EXPECT TO LAND N RWY 36L. PRIOR TO PASSING BGD; TURNED TO S HEADING DUE TFC AND DSNDED TO FL330; THEN CONTINUED TO FL240. ATC TOLD US TO MAINTAIN 320 KTS FOR TFC SPACING. THEN TOLD TO SLOW 280 KTS FOR SPACING AND CLRED DIRECT TO BOWIE. (FO AND I CANNOT REMEMBER IF ATC TOLD US TO RESUME STAR.) WE CONTINUED THE STAR MAINTAINING LAST ASSIGNED IAS OF 280 KTS. WE WERE GIVEN CROSS KAGLE AT 12000 FT; WITH NO MENTION OF SPD. THEN GIVEN AN ASSIGNED HEADING OF 130 DEGS AFTER PASSING SILER; DIFFERENT FROM THE EXPECTED 170 DEGS ON STAR; A CLUE OF POSSIBLE RWY CHANGE FROM THAT ON ATIS. AGAIN NO MENTION OF SPD. AS WE PASSED SILER; WE WERE GIVEN IMMEDIATE R TURN AND TOLD WE DID NOT FOLLOW STAR SPDS. (WE THOUGHT WE WERE ON POSITIVE CTL FROM ATC AND ON AN ASSIGNED IAS OF 280 KTS.) WE WERE GIVEN 210 KTS. ATC ASKED IF WE SAW B727 AT 11 O'CLOCK POS. I ANSWERED YES; AND ATC TOLD US TO FOLLOW HIM. WE ACKNOWLEDGED. I DO NOT KNOW IF OUR SPACING WITH B727 WAS TOO CLOSE FOR ATC RULES; (DID NOT LOOK CLOSE TO US). WE DID NOT GET TCASII; TOOK NO EVASIVE ACTION; ATC DID NOT SAY WE HAVE REDUCED SEPARATION. SOLUTION: DO NOT ASSUME: IF ATC PULLS YOU OFF OF STAR; MUST RE-ESTABLISH THAT YOU ARE BACK ON STAR. POSITIVELY; WE AS PLTS MUST NOT ASSUME ANYTHING AND QUESTION ATC IF TO RESUME STAR ALT AND SPDS. CONTRIBUTING FACTORS: DFW HAS SO MUCH TFC THAT CTLRS TALK MUCH TOO FAST. CAPT DISTRACTED ON COMPANY RADIO; ATIS GAVE EXPECT RWY. ATC CHANGED RWYS 3 TIMES RWYS 36L; 35C; THEN LANDED ON RWY 35R. MAX WORKLOAD ON GLASS/FMS COCKPITS. FROM NOW ON; WILL QUESTION ATC IF ONCE OFF STAR; TO RESUME STAR ALT AND SPDS.