1985 Oldsmobile Delta 88 CHECK ENGINE LIGHT

MY CHECK ENGINE LITE COMES ON THEN GOES OUT.
THIS OCCURS NUMEROUS TIMES WHILE I DRIVE.
I TOOK TO MY LOCAL SERVICE STATION WHILE IT WAS LIT.
THEY HOOKED UP THEIR DEVICE. THE CODE WAS "THROTTLE POSITION SENSOR"
ONE MECHANIC SAYS REPLACE THE CARBURATOR.
ANOTHER SAYS IGNORE IT.
WHERE IS THE TPS?
HOW DO I CHECK IT?
HOW CAN I REPLACE IT?