Tps 90 Runer 3.0 Auto Help!

[MANDARD]

JUST BOUGHT MY 90 RUNNER RAN FINE FOR ABOUT A WEEK THEN NOTICED WHEN HOLDING STEADY SPEED AT 35 OR HIGHER THE RPMS WILL JUMP ABOUT 500 RPMS FOR A SECOND THEN GO BACK TO NORMAL. I WAS TOLD IT WAS THE TPS SO I REPLACED. WHEN WE TEST DROVE IT STOPPED. THE NEXT MORNING THOUGH IT STARTED BACK UP AGAIN. IS THERE A CERTAIN WAY THE TPS NEEDS TO BE ADJUSTED OR IS THERE SOMETHING ELSE GOING ON HERE. ANY HELP WOULD BE GREAT THANKS AMANDA