the 1991 G16a has a pig tail connector, must have 4 wires.
and shares the Injector connector (tricky pin pulls, and all)
that connector you gander is the injector /TPS connector
it has 6 pins but only 4 are for TPS. (yellow /.red are injector)
see page 3 below, for what all this means. last link below.
try to keep in mind, your car has a VIN engine code U (not 6) code 6 , has no pig tail, TPS.
GM uses U code to say, engine is 8valves, TBI, G16a , my guess, (no photos) is your bought TPS is
with tails, and is correct for your 8v engine.
Install, (need feeler gauges to do it)
it's not just thrown on to the car, it must be calibrated.
or the idle switch WILL fail.(and more)
one maker of this TPS is here: (hard to find)
SMP makes one. sMP #TH-147 is for 8V tbi.http://www.fixkick.com/buy-parts.html#TPS
do not use 16valve parts on your car.
here is the calibration steps. http://www.fixkick.com/sensors/tests/TPS-testing.html#8v_FSM_cal
the factory page is herehttp://www.fixkick.com/TPS/TPS-p91.JPGhttp://www.fixkick.com/TPS/TPS-p92.jpg
and page 3 herehttp://www.fixkick.com/TPS/TPS-p93.JPG
the last page shows the tricky pin pulls....
you must pull the old pins.' one by one.
then put in then new TPS pins , in the same places of old
then do the calibration steps above, using feeler gauges.
same basic steps, from 1989 to 1998.
in 1999 they calibrate it to 0.5vdc, only.
later years, it auto-calibrates.
if the new TPS fails to cure the problem
post the symptoms, and win.