Help..new owner with ets problems

Hello all! Just bought my first Polaris ATV to use around my property and for plowing. Picked up what looked like a good deal, 2013 850 le with 74 hours 440 miles with a winch, plow, new tires, handguards and a-arm guards in good condition. Checked out fine when I test drove, but after it sat home unused for two days when I went to use it it stumbled when warming up and pulled a ce code for throttle stuck open. Looked into it and adjusted the throttle cable and next day it was fine…..but now this morning it pulled the code again? WTF? Is there a trick to adjusting the cable or do I possibly have a tps problem? I read about just putting something in the switch to defeat the ets, but I’d at least like to try to fix the problem before I rig it. Any help is greatly appreciated and suggestions where to ride in nj are welcome as well!!!