Ignition timing
 

I have 95 EFI 502 don't know if there is a problem. When timing the eng I shunt the ignitoin and set the tinimg at 10 deg btc ,I then bring up the rpms to 2000, at that point the timing is 19-20 deg btc + - all ok. Bring rpm up to 2800-3000rpms timing at 3100 total advance all ok . Know I remove the shunt and check the timing again, at 2100 timing is about19-21 deg,. Now I just touch the throttle and it jumps up to 3000 rpm ,when the shunt plug was in it throttle up nice,I have no control between 2100-3000 rpm. and the timing is at 60 deg+ btc, or should it be around 31 degrees . I been working on this for a week . I change out ECM, distributor module,and the knock sencor module, and new throttle position sensor, also the tps checks out fine .4 to 5.0 any help thanks