View Full Version : Low Idle When Stopping - Pls help Miahcornell & JefferyG

10-19-05, 09:31 AM
Miahcornell, I did a search about low idle and your thread came up and your problem is exactly what I'm experiencing. Did you every get a fix for your problem? If yes, what is it?:banghead:

JefferyG. this is my problem at exactly.

"I have had a problem that is seemingly getting worse. When I am slowing down to a stop after running at driving speed, the idle will drop to 200rpms for about 3 seconds untill the car stops completely. The oil (http://www.cadillacforums.com/forums/showthread.php?t=43690#) pressure gets low so I feather the throttle for a second to keep the rpms up. What could be the problem?

My car idles at 500 rpms in park by the way, it is a 99 with 102k miles."

To add a little more info on this: the A/C is off and it usually happens when the car is at operating temp, but my idle only drops for a few seconds then goes back to normal. My local Cadillac dealer is says I need a oil pressure sending unit, but I'm doubtful on his fix. Could it be a vacuum leak? Or maybe I do need a oil pressure sending unit. Thanks for any info.


10-19-05, 07:58 PM
Well to tell you the truth I havent had the time to really check it out, so meanwhile Ive been running sea-foam (fuel injector/carb/everything) cleaner through every other tank. It comes in a white can and is about $4 a can. The problem has gotten much better, only drops to about 350rpms once in a while now, instead of <200 at every stop. When it was really bad, I just double footed it a little bit (used to driving a stick so was no big deal)

I have assumptions that it is a vaccum leak, since I had replaced the spark plugs prior to this.
But to tell you an answer, no I dont have one. Have you done any repairs to your car prior to this happening? I really should get off my lazy butt and find the problem, when I do I will post.

PS, Try running your car with the AC on, mine idles 200rpms higher with it on, so it never drops below 500. And possibly disconnecting the battery for a while to reset everything, may just be a low idle?

10-20-05, 09:23 AM
Hey thanks Miahcornell for responding to my post! :) Yes, when you figure it out please post. If you wouldn't mind would you email me. I might have some questions to ask. I had a vacuum leak once, but when that happened the check engine light came on. It was one of the four lines coming off the air intake on top of the engine. I wonder if our problem has anything to do with the brake booster? Any one out there have any input? Thanks again.