how long did you leave the battery unhooked before you reconnected it? if your KOEO TP voltage is .98 with the throttle closed, it should have deleted the code.

I just went through this with my 90, and the code 53 went away when I installed and set a new TP sensor, didn't even unhook the battery to reset the ECU. I am still getting the 82 and 84 codes for the EGR and I have an eliminator plate and a dummy EGR sensor. also getting code 81 (IAC circuit), and the IAC motor and valve are almost brand new.