53 is TPS sensor above maximum voltage.
TPS is the 3 wire sensor on the otherside of the throttle lever (the thing that the throttle cable operates to open the throttle plate in the throttle body). What this does is send a signal to the computer to tell it how much throttle your are applying.
Need an analog meter to test it. One wire is gound, one is 5 volt constant reference voltage, and the other is the signal. You will want to test between the ground and computer signal.
TPS should read ~.9 volts idle to just under 5 volts @ WOT.
The needle on the analog meter should sweep smoothly and consistently when throttle is operated.
Test the TPS and let us know what you find.