Cadillac Repair: 1993 Deville wont idle, vacuum leaks, throttle positioning sensor

Question
QUESTION: Tom, I have a 1993 Deville w/4.9 liter engine. I get an E 26 code(shorted throttle switch circuit) and an E30 code (ISC out of range)The idle speed control plunger is moving to try and keep engine idling, but it conks out anyway--any ideas ?
ANSWER: Could be a misadjusted throttle positioning sensor and or a faulty idle speed control motor.

Also could be that the throttle body and EGR passages need to be cleaned of residue.

Have you adjusted ANYTHING at all on the vehicle as this will only cause additional problems if you do not tell me that you did adjust this or that.


---------- FOLLOW-UP ----------

QUESTION: I replaced the idle speed control motor too, and also the fuel filter---it runs great with no codes---it just won't idle.

Answer
Check for any vacuum leaks around the intake and see if the spark plugs are fouled.

You need to clean the throttle body and If you have adjusted the idle speed by ANY MEANS WHAT-SO-EVER you will need to perform the TPS adjustment , The ISC motor adjustment and the RE-LEARN procedure. E-mail me at: onlineautohelp@msn.com