So my VX finally started with the annoying surging idle.

I pulled the IACV cleaned it and nothing. Still surges when outside air is below 50F If outside air is above ~50F it seems to idle just fine, from cold start until fully warmed up and longer.

I've also noticed that I can (when sitting at a stoplight) hold the idle by engaging the clutch a little and then release it and it will stop surging.

any thoughts on what else to check? I've looked over some vacuum hoses and most are in decent shape no cracks or anything like that.

It just baffles me that it's only when it is "cold" outside.

TIA

 

Have you pulled out and cleaned the Intake Air Temperature sensor ever?

I never seen anyone specify the operation or use of the sensor but all the trims have it so I am sure the ECU uses it for something and you did say the ambient air temp seems to play a role.....

However, most likely your IACV has finally bit the dust. It took me 3 used ones to stable out my idle.

 

I'll pull the IAT tonight and give it a cleaning...

 

Test the ECT sensor, it may be out of spec giving false reading during cold weather/ cold start.