Cold Engine Bouncing Idle
#1
Advanced
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I noticed the other day when I started my 951 up, the idle seemed a little unstable until the engine warmed up. Revs go up as usual on initial start, drop towards 850 rpm, then seem to drop below to 750-800 rpm before returning to normal idle speed. It bounces between 750-850 about twice per second for the first 30 seconds of operation if sitting in a parking spot, but once I've accelerated a couple times when driving, things stabilize and never drop below 850 again. Almost like the computer is taking an extra half second to catch the falling idle. Thoughts as to what I should check?
#2
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Your Digital Idle Stabilizer is sticking and cannot keep up with the signal from the ECU. Either replace it with a good one or remove it, clean the interior with brake cleaner and reinstall..
#4
Advanced
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Idle control valve maybe? It's tucked under the inlet manifold so I pain in the rear to swap out. You CAN try cleaning it with carb cleaner - the one hose connects to the inlet manifold between the two front most cylinders, so you can pull that off and with a long tube on the carb cleaner nozzle give it a good squirt or 3.