Loss of power when accelerating

The problem is total advance only works the instant driver come off of throttle, traveling at 3000rpm the advance is reading is 12 degrees at 60% throttle position. The second one takes their foot off of the gas it will spike up to 30 plus degrees for a split second. Very sluggish on take off, no power on take off, idle is perfect at 8 to 12 degrees. The advanced timing makes changes but not at proper times. What sensor controls the computer to know where the issue is or is there another problem to solve?

Vehicle goes into reduced engine power. Get code for accelerator position sensor and throttle position sensor.
Replaced accelerator position sensor, problem happens less often but not solved.