Narrative:

We had descended the aircraft from FL370 to FL310 because of turbulence. The ride had improved at higher altitudes; so we were climbing back up to FL370. First officer was flying. I noticed; shortly after we began to climb; that the aircraft was not climbing at its normal rate; only attaining about 500 FPM. At that point the first officer pointed out that the right engine EPR was not anywhere near equal to the left engine's normal climb power; only powering up to about 1.4 EPR. The 2 throttles were together on the quadrant; at a normal climb position. We advanced the right throttle to the forward stop; and the right engine EPR did not advance with it; and other engine indications on the right engine were also not equal to the left engine. It was obvious that the right engine was not developing power. I found little guidance in the QRH; and prepared for a single engine landing. We notified ATC that we would be diverting to ZZZ1; declared an emergency; and asked for the arff equipment to stand by. I did not shut the engine down; it was operating normally at low power settings. We did prepare for a single engine landing and go around; however; just in case the engine quit entirely or we were required to go around with little power from the right engine. We did a normal 2 engine landing; without incident. First officer was a great asset in this incident; was focused and did a great job of flying the aircraft.

Related reports:

Google
 

Original NASA ASRS Text

Title: B757-200 RIGHT ENG FAILED TO RESPOND TO THROTTLE MOVEMENT DURING CLIMB. FLT CREW DECLARED AN EMER AND DIVERTED.

Narrative: WE HAD DSNDED THE ACFT FROM FL370 TO FL310 BECAUSE OF TURB. THE RIDE HAD IMPROVED AT HIGHER ALTS; SO WE WERE CLBING BACK UP TO FL370. FO WAS FLYING. I NOTICED; SHORTLY AFTER WE BEGAN TO CLB; THAT THE ACFT WAS NOT CLBING AT ITS NORMAL RATE; ONLY ATTAINING ABOUT 500 FPM. AT THAT POINT THE FO POINTED OUT THAT THE R ENG EPR WAS NOT ANYWHERE NEAR EQUAL TO THE L ENG'S NORMAL CLB PWR; ONLY POWERING UP TO ABOUT 1.4 EPR. THE 2 THROTTLES WERE TOGETHER ON THE QUADRANT; AT A NORMAL CLB POS. WE ADVANCED THE R THROTTLE TO THE FORWARD STOP; AND THE R ENG EPR DID NOT ADVANCE WITH IT; AND OTHER ENG INDICATIONS ON THE R ENG WERE ALSO NOT EQUAL TO THE L ENG. IT WAS OBVIOUS THAT THE R ENG WAS NOT DEVELOPING PWR. I FOUND LITTLE GUIDANCE IN THE QRH; AND PREPARED FOR A SINGLE ENG LNDG. WE NOTIFIED ATC THAT WE WOULD BE DIVERTING TO ZZZ1; DECLARED AN EMER; AND ASKED FOR THE ARFF EQUIP TO STAND BY. I DID NOT SHUT THE ENG DOWN; IT WAS OPERATING NORMALLY AT LOW PWR SETTINGS. WE DID PREPARE FOR A SINGLE ENG LNDG AND GAR; HOWEVER; JUST IN CASE THE ENG QUIT ENTIRELY OR WE WERE REQUIRED TO GO AROUND WITH LITTLE PWR FROM THE R ENG. WE DID A NORMAL 2 ENG LNDG; WITHOUT INCIDENT. FO WAS A GREAT ASSET IN THIS INCIDENT; WAS FOCUSED AND DID A GREAT JOB OF FLYING THE ACFT.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.