safleming72 Posted July 29, 2008 Report Share Posted July 29, 2008 Over the weekend I experienced a new problem that I need some help with. On Sat I was driving and came to a stop and when I did the idle speed did not fall all the way down to a normal idle. It did this everytime I came to a stop, until I pulled into a parking lot and killed it. When I started it back up it reved up to the same higher idle but after about 20 seconds it slowly dropped back down to a normal idle. I drove around for about 2 hours and also drove some on Sunday but it never happened again. Today it did the same thing on my way to work, came to a stop, had a high idle, pulled over, killed it, started it with a high idle and then it slowly dropped back down. Any ideas and suggestions would be greatly appreciated. Thanks - Shane Link to comment Share on other sites More sharing options...
safleming72 Posted July 29, 2008 Author Report Share Posted July 29, 2008 FORGOT TO ADD THAT IT IS NOT THROWING ANY CODES WHEN IT DOES THIS. Link to comment Share on other sites More sharing options...
BodybyFisher Posted July 29, 2008 Report Share Posted July 29, 2008 Clean your throttle body. Clean the throat, and edges and back of the throttle plate. Use GM upper engine cleaner, rags and a detail brush or tooth brush. It will take about 30 minutes to clean it really good, clean the back of the plate. DO NOT pour or pool the solvent in the intake!, you can hydrolock the engine. When you get done, it should shine. Disconnect the battery, to let your system go through a relearn. IF it still races after you clean the TB, it could also be your ISC motor on the 94, I think.. Do you hear clicking?, I think you have an ISC on that year, do you know? Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
safleming72 Posted July 29, 2008 Author Report Share Posted July 29, 2008 I'm not sure if it has the ISC or not, I have'nt had a chance to check, but I have not heard it clicking. This weekend I will definately get out there and give her a thorough cleaning. Thanks! Link to comment Share on other sites More sharing options...
Barry94 Posted July 30, 2008 Report Share Posted July 30, 2008 The '94's definitely have an ISC and the symptom you describe is exactly how they fail. I've had mine out three times in the past 12 years for the same problem. Clean your throttle body anyway as suggested, you may get lucky. The problem with the ISC is a set of points get closed when you release the throttle. The throttle linkage depresses a plunger on the ISC that closes the points inside the ISC. The points get dirty and although they get closed, they don't make electrical contact. The engine computer never gets the signal to go to idle mode. Quite awhile ago I posted a "how to" on repairing the ISC. (With Pictures) If you determine it's your ISC and want to tackle repairing it, check the archives. Barry 2008 STS V82016 Colorado Z711970 Corvette LT-1 Coupe Link to comment Share on other sites More sharing options...
lothos Posted July 30, 2008 Report Share Posted July 30, 2008 It's actually a very good post. http://caddyinfo.ipbhost.com/index.php?sho...amp;mode=linear I tried adjusting mine and testing it through the dash computer, but it still needs to be replaced. I've got the part, just haven't gotten around to it yet. WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn. Cheers! 5% discount code at RockAuto.com - click here for your discount! Link to comment Share on other sites More sharing options...
safleming72 Posted July 30, 2008 Author Report Share Posted July 30, 2008 Thanks for the help and the link to the original post. I plan on cleaning the throttle body this weekend and changing the isc if it is necessary. Link to comment Share on other sites More sharing options...
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