So in order to take care of the trans vibrations I've been having I am replacing every part of the mounts and support assembly. So far so good, but one thing has me thinking... Why when the engine is cold will my idle act lumpy, but be normal with the clutch depressed? I'm beginning to wonder if something is up with the clutch/pressure plate assembly. It shifts like a dream, but I just have a gut feeling something is up inside there... Any thoughts on it?

I'm going to attempt to give it some beans and go through the rpm range after everything is fully swapped in and my fluid is changed before I unbolt the trans from the engine, so until then, please help me speculate

 

If idle changes when clutch pedal is pressed....could be a thrust bearing issue.

 

there's a switch at the top of the clutch which is struck when your foot is OFF the clutch, which is an input into the ECU. I think it's that, & nothing mechanical.

 

+1

 

Had this issue with my GSL-SE. hot or cold, i had two different idle's, one hunting, one solid. i believe the ecu changes the idle"load" based on this input, i just jumped it off, so that it thinks the clutch is always in, my starter signal wire already bypass'd it anyways... it also solved the mystery of my hard starts, the ECU doesnt currently know when i am strating or not.

 

press the switch manually, without pressing the clutch pedal and see if it changes..

 

I'll have to try that in the morning before school. So say that works, where should I go from there? I have the full '89 FSM on my iPad for easy access so if that helps give an answer easier then good.

 

You guys were right, its the clutch sensor thing-a-mabob. What's the next course of action I should do? I suck with electrical

 

Replace it? Haha

 

Replacing it wont help, the switch actually works..

The problem is in the ecu (NO, this does not mean you have to get another ecu!)
It been a long time for me to have worked with a stock FC, so i dont know for sure. But i think you might want to start with checking the TPS, and your cold-start accessories