Helping a friend with a 2000 Civic Ex. The car has no check engine lights and no vacuum leaks. Once the car reaches operating temp at a stop the engine will drop to roughly 400 rpms idle speed and almost stall. At this point the whole car shakes due to the extremely low idle. Eventually the idle will pick up to around 1000 rpms and then it drop again to 400 rpms and repeat the same issue over and over again..

I've replaced the Idle air control valve and it didn't fix the problem. I figured it wouldn't but I wanted to rule it out. Any issue I've had relating to an IACV problem usually causes rapid idle fluctuation from 900rpms to higher rpms. This car just wants to stall but it doesn't.

If I disconnect the TPS sensor, the problem does not occur. It will idle around 1000 rpms and obviously the Check Engine Light will appear.

Any input on the problem is appreciated

 

Check whether the TPS output voltages are properly calibrated and, if so, then adjust the idle speed to spec (see FAQs sticky for proper method).

 

I checked the TPS output voltages and they were within factory specs. The problem still exists. Here is a video for reference. Nevermind the guy in the background stating "the compression is horrible". Engine compression has been checked already.

http://www.youtube.com/watch?v=Aid5rDnc2Bw

 

car wont idle with missing or bad 02 sensor dont skip that even if everything else is perfect. both o2s if you need em obd1 uses 1

 

x2 adjust the idle valve...