Recently purchased a second D2, a 99. The idle speed is a little high once it warms up. Wondering if the idle air controller is responsible for this and whether it might be adjustable. Also noticed that the cruise control is inop,...and do have some broken vacuum lines at the cruise unit,.....could this cause the problem?

Brian in Austin.

 

The vac lines could definitely cause that. I'd fix the vac lines and check your throttle cable tension to see if its holding the throttle open any. I'd almost guarantee its the vac lines.

 

Alex, replaced the vac line,. Good news is that my cruise is working again,.....however my idle speed is the same,.....about 900 by my tach

 

Do you have any way to read O2 data? Might have a vac leak somewhere else. And have you double checked the throttle cables?

 

Yes, my scan tool can check O2 sensor readings. Not sure what reading I am looking for though. I did make a throttle cable adjustment a few weeks ago,,..I'll check it in the morning

 

Your tach might be wrong, typical Land Rover quality. I'd compare it to live data from the obd2

 

Checked it with my scan tool as well,....and can tell just by the sound of it compared to my 03 D2 ( and two other prior D2s)

 

The computer adjusts the idle on a D2. At least, that's all I could find out when I was wondering about my own idle.

When my engine runs bad and I can't find a physical problem I just unplug sensors until it stops running bad. I always start with the MAF. But your idle air control valve could also be dirty.

 

Sounds like it might be connected somehow.

 

check the throttle cable. after replacing the intake plenum, I put mine on wrong and had idle of about 1800 rpm and quickly shut it down, found the issue and adjusted.

Also...what size (diameter) is that hose for the cruise control? Need to pick up some for mine too.