Cadillac Repair: 88 Cadi - deville RPM goes high, throttle position sensor, number combinations

Question
 -------------------------    Followup To    Question -   Problem with this car is as long as the wheels are moving the RPM stays up around 1500 – 2000 RPM with no foot on the accelerator. When the car  speed drops below 7kph or total stop the RPM drops to normal(600-700) without you doing anything to the gas pedal.     I  also tested this problem with the car standing on top of the hill(in NETURAL, car running) where the car can roll forward on its own without you touching the gas pedal. The car is going down the hill and picking up speed(anything over 10kpm) and you can feel the RPM going up(NETURAL and no gas pedal being pressed). Then you are slowing down to stop you can hear the RPM being high and by the time car is almost at a stop or come to toal stop the RPM has gone down again.    Remember I did not touch the gas pedal when I started down the hill or when I came to a full stop.    The actuator and Oxygen Censor was replaced two months    Answer -   Sounds like a faulty TPS (Throttle Position Sensor and or a faulty ISC (Idle Speed Control) motor.    1. Ignition ON, Engine OFF.    2. Locate the OFF and WARMER buttons on you climate control panel.    3. Push and hold simoultaneously the OFF and WARMER buttons for 2 seconds and release them.    4. Write down and letter or number combinations appearing on the screen until it stops on .7.0    5. Let me know the letters/numbers displayed.    6. Turn ignition OFF.    

Today the error codes show as
8.8.8
. .E
E48 - With service soon light on after driving 20 minutes on the freeway this light came on. After shutting down the engine and started back the light went out but left this code.

E52 - is still there.
.7.0
Hope you can help.  

Answer
8.8.8 is normal as it is just the computer going into the code display sequence.

The E48 means that you have a fault in the EGR system.

E52 means that the battery was disconnected.

.7.0 is Normal as it is another computer sequence.

Once we gwt the E48 taken care of we will erase all the codes and all you will see is the 888 and 70 sequences.

Due to the long diagnostics procedure that you must do.

You will need to contact me at:


onlineautohelp@msn.com


In order for me to provide you with pictures and and electrical schematic to find and fix your problem since this board does not allow sending pictures.



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