BGS300

My 1998 GS300, 190,000 miles just started bucking and almost stalling out at idle or when I start to slow down to stop. Code P1128 says throttle control motor malfunction or lock. Has anyone had xperience with this? I want to check the TCM with an Ohm meter but there are too many wires and I have no mechanics manual for this. Otherwise i will just replce the unit and hope for the best. sidenote: all of this started after the front left lower ball joint went out and was replaced.