1992 eldorado E30 and E52 error
 

I have a 1992 eldorado 4.9 motor with error codes E30 andf E052 ECM Memory Reset Indicator and I052 but the car will start fine then the RPMs will race to 15000 - 2000 and will not kick down can anyone help Please?
The old owner came over and popped the hood and used the engine to race the engine and the idle kicked down but will stall unless I drive the car and give it gas for a little while could my whole problem be the cable sticks for the accelerator. I cleared the codes and I am not getting the e52 or e30 and the check engine light is off but now when i start the car it puutts like it wants to stall but if I drive it it levels out any ideas !!!!! But then the engine will race about a week later with the same codes e30 and e52 and I am not disconnecting the battery ...