84’ cab 3.2L hot idle issue

[PK 77 911]

This one is a little different from a lot of the other threads that I have read.

The car starts and warms up as it should. When it reaches full operating temperature is when the idle issue starts.

It is not really a surge but more of a 1 second stop or cut out then it goes back to it’s usual 1000 to 1100 rpm. 5 or 10 seconds later it repeats. The idle isn’t really jumping all over the place. When the engine temperature drops a bit, like if I turn it off for 10 minutes it will go away until it heats up. Sitting in traffic or just idling causes it to do it continually. It does not do this prior to reaching full operating temperature.

It has an O2 sensor which I disconnected. There is no change when it is disconnected.

Any Thanks for your advice.

[76FJ55]

For reference, 1000 to 1100 is too high. A warm engine should have an idle of 800+/-40.

If you think it is due to the CHT sensor, you can always unplug it an install a jumper wire into the chassis side connector to simulate a hot engine (low resistance) once the engine is warmed up.

[PK 77 911]

Ok I will give that a try. Thank you.